D31.01 - Vegetable Leather

SIGNIFICANCE AND USE
5.1 This test method is used to determine the proportion of the total solids which are soluble solids and that proportion which are insoluble solids in a solution of tannin extract or in the water extract from raw or spent materials prepared for tannin analysis.  
5.2 The specimens are aliquots from the analytical solutions prepared from tannin extracts or the water extract solutions prepared from raw or spent materials.  
5.3 The soluble solids are defined as the portion of the total solids which are dissolved in the water and pass through a filter prepared by depositing a layer of Kaolin paste onto a standard filter paper.  
5.4 The insolubles are defined as the portion of the total solids which do not pass through the standard filter paper prepared with the layer of Kaolin paste.  
5.5 The results of this test method are dependent on a great many variables but particularly upon:  
5.5.1 The temperature conditions under which the solutions were prepared and stored and the temperature at which the current analysis is performed;  
5.5.2 The uniformity and consistency of the Kaolin paste layer deposited onto the filter paper;  
5.5.3 The rate of solution run-out from the pipette; etc. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining the quantity of soluble solids and insolubles in solutions of tannin extracts, water extracts of vegetable tanning materials, or tanning liquors. This test method is applicable to the analysis of liquid, solid, pasty, and powdered tannin extracts and to the water extracts of raw or spent materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The concentration of tannin in extracts must be reduced to analytical strength (4 g tannin per L) for analysis.  
4.2 Vegetable tannin extracts are heterogeneous mixtures of components with varying solubility.  
4.3 The solubility of such extracts is influenced by temperature and concentration, which affect the degree of dispersion and size of the component particles.  
4.4 While the solubility is better in hot water than in cold water, it is appropriate to dissolve and disperse an extract in hot water and then let the solution cool slowly to standard room temperature.
SCOPE
1.1 This practice covers the preparation of a solution of liquid extract that is to be used in the tannin analysis of that extract.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is designed to determine the cracking resistance of the grain or finish surface of leather on a pass/fail basis. This test method attempts to replicate the conditions that may be encountered by leather that is bent around a buckle frame or other anchoring device, folded over in seams or welts, and so forth. The cracking resistance of leather is influenced by many factors such as quantity, location, and type of fatliquoring materials; moisture content; thickness; the presence of defects or scar tissue, or both; the presence of processing damages to the skin or hide tissue; finish system formulation, and so forth. This test method is useful for manufacturing control in the tannery, specification acceptance, and quality control in the end product manufacturing plant.
SCOPE
1.1 This test method covers the determination of the resistance of leather to cracking when the leather is bent or folded with the grain (or finish) surface on the outside of the bend. Heavy leathers (for example, harness, belt, strap, bag, case, and so forth) are usually bent around a mandrel using either mechanical resistance (for example, clamp, vise, and so forth) or by hand. Lighter leathers (for example, shoe upper, upholstery, garment, glove, and so forth) are usually given a sharp double-fold (crosswise) bend after cooling to a low temperature. This test method does not apply to wet blue.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The procedure is primarily intended to evaluate corrosion produced by leather in contact with metals or metal objects that are used in construction and production of upholstery, briefcases, watches, jewelry, gun holsters, knife sheaths and any other circumstances where leather is in direct contact with various metal hardware and under circumstances where metal corrosion is a serious factor. A high relative humidity and increased temperature is used for the purpose of accelerating the results.  
5.2 The relative corrosion severity rating system is provided in order to allow a numerical classification of the test results and to eliminate the necessity for elaborate weight loss measurements. Pitting corrosion, which is rated 4—extensive (severe) corrosion, may involve only a negligible weight loss.
SCOPE
1.1 This test method covers the qualitative determination of corrosion produced by leather in contact with metal. This test method does not apply to wet blue or wet white.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This practice provides standard procedures for obtaining representative samples of various materials used as a source of tannins for the tanning industry.  
5.2 Procedures are described for obtaining representative samples of economical and convenient quantities from a lot, or sections of a lot, of material for examination and analysis so that agreement may be reached with regard to the extent of variation of quality in different portions of a lot and the average quality of the entire lot of material.  
5.3 No directions for sampling, however explicit, can take the place of judgment, skill, and previous experience on the part of persons actually engaged in the sampling or the supervision of the sampling. These directions are intended to supplement that experience and, particularly, to serve as a guide in the selection of the method which is to be used, in common, by each of two or more contracting parties.  
5.4 Tanning materials contain moisture in varying amounts, depending both on the nature of the material and on the climatic conditions, so that sampling must be carried out as quickly as is consistent with thoroughness in order to avoid changes in moisture content.
SCOPE
1.1 This practice covers obtaining representative samples from shipment lots of botanical materials containing tannin.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method is useful for determining the solid residue in analytical solutions.  
4.2 Because of the possibility of unknown errors in this test method, it is essential that the procedure be followed exactly in order to obtain reproducible results, both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method covers a procedure for the evaporating and drying of the 100 mL portions of analytical solution obtained in the methods for vegetable tannin analysis, so that consistent results may be obtained for the determination of total solids, soluble solids, and non-tannins in the sample. This test method is also intended for use in determining the moisture in the hide powder samples and the moisture in raw and spent materials in the methods for vegetable tannin analysis.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the chemical properties of tannery liquors which are relevant for the vegetable tanning process and influence the astringency of vegetable tanning liquors. The astringency of liquors is dependent upon the solids and tannin content and the acidity. This method provides a standard procedure for determining these properties for any sample of vegetable tanning liquor.  
5.2 The specimens are aliquots from the analytical solution prepared from the sample of tannery liquor collected for this purpose.  
5.3 The total solids, soluble solids, and non-tannins content are determined and then the tannin content of the liquor sample is calculated. Because the amount of tannin per liter of analytical solution is less than that required for Test Method D6401, a table specifying the quantity of prepared hide powder to be used for solutions with lower tannin concentrations is included in this test method.  
5.4 The total acidity of the liquor sample is determined by one of two titrametric procedures described in Test Method D6410.  
5.5 The results of this test method are dependent on a great many variables but particularly upon: the temperature conditions under which the solutions were prepared and stored and the temperature at which the current analysis is performed; the uniformity and consistency of the Kaolin paste layer deposited onto the filter paper; the rate of solution run-out from the pipette; conditions related to the properties of the hide powder used to react with the tannin content of the solution; etc. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method covers the analysis of tannery liquors made up from vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
3.1 This test method is intended to be used to rate leathers as to their stitch tear strengths.
SCOPE
1.1 This test method is intended for determining the stitch-tearing strength of leather with a tear originating from one hole. It is particularly applicable to heavy leather. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The test method is useful for determining the water-soluble materials in vegetable-tanned leathers.  
4.2 The water-soluble matter includes the soluble nontanning components of the tanning materials used, sugars and materials of a similar nature, and inorganic compounds such as Epsom salts, Glauber's salts, borax, and other soluble salts added during curing and tannery processing.
SCOPE
1.1 This test method covers the determination of the water-soluble materials in all types of vegetable-tanned leathers. This test method does not apply to wet blue.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method gives the amount of ash remaining in the specimen after water extraction to remove water solubles from the leather in accordance with Test Method D2876. The insoluble ash is used in calculating the combined tannin because it is part of the tanned fiber structure that does not leach from the leather during water extraction.
SCOPE
1.1 This test method covers the determination of the insoluble ash in all types of vegetable-tanned leathers. This test method does not apply to wet blue.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method is useful in determining the total solids and water in analytical solutions.
SCOPE
1.1 This test method is intended for use in determining the total solids and water in extracts of vegetable tanning materials. The test method is applicable to solutions of liquid, solid, pasty, and powdered extracts, and to extracts of raw or spent materials.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the quantity of sugar present in vegetable tanning materials or vegetable tannin extracts. The amount of the reducing sugars, total sugars, and non-reducing sugars in a sample of material or extract can be determined by this method.  
5.2 Because of the possibility of errors in this test method it is essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method covers determining the sugars present in vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This practice provides a standard procedure for obtaining the water-soluble materials (including tannins) from any material that can be prepared for and charged to the steam-jacketed extractor. The extraction solutions are then analyzed according to Test Methods D4903, D6401, and D6402.
SCOPE
1.1 This practice covers extracting the tannin from raw and spent materials. The water extract obtained by this method is used to determine the tannin content of the original material. Analysis for total solids, soluble solids, and soluble non-tannins of the water extract from a material provides the information necessary to calculate the extractable tannin content of that material. The types of materials typically analyzed by this practice are products of plants such as woods, barks, leaves, nuts, fruits, roots, etc. and any of a wide variety of by-products (spent materials) from industrial processes utilizing plant products.  
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is used to determine one of the chemical properties of tannery liquors which are relevant for the vegetable tanning process and influence the astringency of vegetable tanning liquors. The astringency of liquors is dependent upon the solids and tannin content and the acidity. This test method provides a standard procedure for determining the total acidity for any sample of vegetable tanning liquor.  
5.2 The specimens are aliquots from the analytical solution prepared from the sample of tannery liquor collected for this purpose.  
5.3 The total acidity of the liquor sample is determined by one of two titrametric procedures described in this test method.
SCOPE
1.1 This test method covers determining the acidity of tannery liquors made up from vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
3.1 Vegetable tanning materials are natural products containing various substances of varying composition, concentration and quality.  
3.2 The methods referenced are useful for analyzing and testing vegetable tanning materials for moisture, water-extractable substances, cold-soluble fractions, tannins, non-tannins, acidity, tanning properties, the color of tanned leather, and the presence or absence of certain admixtures.
SCOPE
1.1 This practice is intended for use in the chemical analysis of all vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method is used to determine the quantity of iron and copper present in vegetable tanning materials or vegetable tannin extracts prepared using Practices D4901, D6404, or D6405.  
4.2 Because of the possibility of errors in this test method it is essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining iron and copper content in vegetable tanning materials. This test method is applicable to liquid, solid, pasty and powdered extracts, to raw and spent materials, and to tannery liquors.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
3.1 This practice may be used to determine non-protein or non-nitrogen containing organic matter in leather which is not extractable with water or hexane. Examples would be vegetable tannins and acrylic lubricants.
SCOPE
1.1 This practice covers the determination of the combined tannin and nonextractable organic resins and the degree of tannage of all types of vegetable-tanned leather and leather with organic retannages. This practice does not apply to wet blue.  
1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The concentration of tannins in solid, pasty, and powdered extracts needs to be reduced to analytical strength for tannin analyses.  
4.2 Vegetable tannin extracts are heterogeneous mixtures of components with varying solubility.  
4.3 The solubility of such extracts is influenced by temperature and concentration, which affect the degree of dispersion and size of the component particles.  
4.4 Since extracts have greater solubility in hot water than cold, it is desirable to dissolve and disperse an extract in hot water and then let the solution cool slowly to standard room temperature.  
4.5 It is often difficult to reduce samples of solid and particularly pasty extracts to specimen size and at the same time ensure representative sampling. Therefore, caution is advised in drawing conclusions on the precision and bias of the results obtained on such extracts; where difficulties in sample preparation are experienced, little confidence can be placed in the results.
SCOPE
1.1 This practice covers a standard procedure for use in preparing the analytical solution required for the analysis of solid, pasty, or powdered vegetable tannin extracts.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Compressibility is considered an important factor that influences wear resistance of sole leather.3,4
SCOPE
1.1 This test method covers the determination of the compressibility of sole leather. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
2.1 This test method is designed to measure the load required to tear a leather strap fastened in a buckle. Tanners and leather buyers have found that this test gives an indication of the resistance of leather to tearing.  
2.2 This test method should be suitable for specification acceptance, design purposes, manufacturing control, development, and research. The thickness of the specimen and direction of tear relative to the backbone will affect the uniformity of the test results. This test method may not apply when the conditions of the test employed differ widely from those specified in this test method.
SCOPE
1.1 This test method is intended for use on all types of leather to determine the load required to tear a leather strap fastened in a buckle. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the moisture content of materials (raw or spent) that are to be extracted for tannin analysis. The value obtained for moisture content by this test method is used to calculate the results of the other analyses on this material to a moisture-free basis.  
5.2 The specimens are obtained from the material prepared for extraction in Practice D6405.  
5.3 Tanning materials contain moisture in varying amounts, depending both on the nature of the material and on the climatic conditions, therefore sampling must be carried out as quickly as is consistent with thoroughness in order to avoid changes in moisture content.  
5.4 Negative errors may occur in the moisture determination because under the conditions of this method there may be retention of moisture by certain components (for example, hydrated salts or water bound to organic structures) of the raw or spent material or because of oxidation of other components (for example, tannins) of the raw or spent material.  
5.5 Positive errors may occur in the moisture determination because under the conditions of this test method there may be volatilization of certain components of the raw or spent material other than water.  
5.6 It is known that other factors can also affect the quantity of volatile matter (moisture) released by the specimen. These factors include but are not limited to: particle size of the test specimen, quantity of test specimen, oven temperature, exposure time in the oven, shape of the specimen container, and type of oven (for example, gravity or mechanical convection) used.  
5.7 Because of the possibility of unknown errors in this test method it is essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining the moisture content in raw and spent materials that are extracted for tannin analysis. The moisture content of the sample is operationally defined to be equal to the weight loss experienced as a result of the evaporation which occurs in the drying oven.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The solubility of extracts is influenced by temperature. The analytical solutions prepared from tanning extracts are dissolved or diluted in hot water. It is necessary to exercise caution in cooling these solutions, and to do so in such a way as to avoid chilling, under-cooling, or uneven cooling of the solutions.
SCOPE
1.1 This practice covers a standard procedure for the cooling of analytical solutions such as those prepared in Practices D4901, D4905, or D6405. The tannin analysis results for an analytical solution are to some extent dependent on the conditions of the cooling of that solution.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method is useful to detect possible adulteration of tanning material extract with cheap and inferior lignosulfonates.
SCOPE
1.1 This test method is intended for use in detecting the presence of lignosulfonates (sulfite cellulose) in extracts of tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the proportion of the total soluble solids which are soluble non-tannins and the proportion which are tannins in a solution of tannin extract or in the water extract from raw or spent materials prepared for tannin analysis.  
5.2 The specimens are aliquots from the analytical solutions prepared from tannin extracts or the water extract solutions prepared from raw or spent materials.  
5.3 The soluble non-tannins are defined as the portion of the soluble solids which are not absorbed or bound by a prepared hide powder material.  
5.4 The tannins are defined as the portion of the soluble solids which are absorbed or bound by a prepared hide powder material.  
5.5 The results of this test method are dependent on a great many variables, but particularly upon:  
5.5.1 The temperature conditions under which the solutions were prepared and stored and the temperature at which the current analysis is performed;  
5.5.2 The uniformity and consistency of the Kaolin paste layer deposited onto the filter paper;  
5.5.3 The rate of solution run-out from the pipette;  
5.5.4 Conditions related to the properties of the hide powder used to react with the tannin content of the solution; etc. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining the quantity of soluble non-tannins and tannin in solutions of tannin extracts, water extracts of vegetable tanning materials, or tanning liquors. The method is applicable to the analysis of liquid, solid, pasty, and powdered extracts and to extracts of raw or spent materials.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses after SI units are for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This practice provides a standard procedure for comparing the color of leather tanned with different tanning extracts or mixtures of extracts or for monitoring the color consistency of tannery liquors.
SCOPE
1.1 This practice covers making color tests of all types of vegetable tanning extracts and of vegetable tanning materials to determine the color imparted to tanned skins.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The procedure is primarily intended to evaluate chrome leather intended for use in hydraulic systems under circumstances where metal corrosion is a serious factor. A high relative humidity is used for the purpose of accelerating the results.
SCOPE
1.1 This test method covers the qualitative and quantitative determination of corrosion produced by leather in contact with metal. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as the standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
2.1 This test method is designed to measure the load required to tear a leather strap fastened in a buckle. Tanners and leather buyers have found that this test gives an indication of the resistance of leather to tearing.  
2.2 This test method should be suitable for specification acceptance, design purposes, manufacturing control, development, and research. The thickness of the specimen and direction of tear relative to the backbone will affect the uniformity of the test results. This test method may not apply when the conditions of the test employed differ widely from those specified in this test method.
SCOPE
1.1 This test method is intended for use on all types of leather to determine the load required to tear a leather strap fastened in a buckle. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The test method is useful for determining the water-soluble materials in vegetable-tanned leathers.  
4.2 The water-soluble matter includes the soluble nontanning components of the tanning materials used, sugars and materials of a similar nature, and inorganic compounds such as Epsom salts, Glauber's salts, borax, and other soluble salts added during curing and tannery processing.
SCOPE
1.1 This test method covers the determination of the water-soluble materials in all types of vegetable-tanned leathers. This test method does not apply to wet blue.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The concentration of tannins in solid, pasty, and powdered extracts needs to be reduced to analytical strength for tannin analyses.  
4.2 Vegetable tannin extracts are heterogeneous mixtures of components with varying solubility.  
4.3 The solubility of such extracts is influenced by temperature and concentration, which affect the degree of dispersion and size of the component particles.  
4.4 Since extracts have greater solubility in hot water than cold, it is desirable to dissolve and disperse an extract in hot water and then let the solution cool slowly to standard room temperature.  
4.5 It is often difficult to reduce samples of solid and particularly pasty extracts to specimen size and at the same time ensure representative sampling. Therefore, caution is advised in drawing conclusions on the precision and bias of the results obtained on such extracts; where difficulties in sample preparation are experienced, little confidence can be placed in the results.
SCOPE
1.1 This practice covers a standard procedure for use in preparing the analytical solution required for the analysis of solid, pasty, or powdered vegetable tannin extracts.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method is useful in determining the total solids and water in analytical solutions.
SCOPE
1.1 This test method is intended for use in determining the total solids and water in extracts of vegetable tanning materials. The test method is applicable to solutions of liquid, solid, pasty, and powdered extracts, and to extracts of raw or spent materials.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
3.1 This test method is intended to be used to rate leathers as to their stitch tear strengths.
SCOPE
1.1 This test method is intended for determining the stitch-tearing strength of leather with a tear originating from one hole. It is particularly applicable to heavy leather. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
3.1 Vegetable tanning materials are natural products containing various substances of varying composition, concentration and quality.  
3.2 The methods referenced are useful for analyzing and testing vegetable tanning materials for moisture, water-extractable substances, cold-soluble fractions, tannins, non-tannins, acidity, tanning properties, the color of tanned leather, and the presence or absence of certain admixtures.
SCOPE
1.1 This practice is intended for use in the chemical analysis of all vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The solubility of extracts is influenced by temperature. The analytical solutions prepared from tanning extracts are dissolved or diluted in hot water. It is necessary to exercise caution in cooling these solutions, and to do so in such a way as to avoid chilling, under-cooling, or uneven cooling of the solutions.
SCOPE
1.1 This practice covers a standard procedure for the cooling of analytical solutions such as those prepared in Practices D4901, D4905, or D6405. The tannin analysis results for an analytical solution are to some extent dependent on the conditions of the cooling of that solution.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 Compressibility is considered an important factor that influences wear resistance of sole leather.3 ,4
SCOPE
1.1 This test method covers the determination of the compressibility of sole leather. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
3.1 This practice may be used to determine non-protein or non-nitrogen containing organic matter in leather which is not extractable with water or hexane. Examples would be vegetable tannins and acrylic lubricants.
SCOPE
1.1 This practice covers the determination of the combined tannin and nonextractable organic resins and the degree of tannage of all types of vegetable-tanned leather and leather with organic retannages. This practice does not apply to wet blue.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the proportion of the total soluble solids which are soluble non-tannins and the proportion which are tannins in a solution of tannin extract or in the water extract from raw or spent materials prepared for tannin analysis.  
5.2 The specimens are aliquots from the analytical solutions prepared from tannin extracts or the water extract solutions prepared from raw or spent materials.  
5.3 The soluble non-tannins are defined as the portion of the soluble solids which are not absorbed or bound by a prepared hide powder material.  
5.4 The tannins are defined as the portion of the soluble solids which are absorbed or bound by a prepared hide powder material.  
5.5 The results of this test method are dependent on a great many variables, but particularly upon:  
5.5.1 The temperature conditions under which the solutions were prepared and stored and the temperature at which the current analysis is performed;  
5.5.2 The uniformity and consistency of the Kaolin paste layer deposited onto the filter paper;  
5.5.3 The rate of solution run-out from the pipette;  
5.5.4 Conditions related to the properties of the hide powder used to react with the tannin content of the solution; etc. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining the quantity of soluble non-tannins and tannin in solutions of tannin extracts, water extracts of vegetable tanning materials, or tanning liquors. The method is applicable to the analysis of liquid, solid, pasty, and powdered extracts and to extracts of raw or spent materials.  
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The concentration of tannin in extracts must be reduced to analytical strength (4 g tannin per L) for analysis.  
4.2 Vegetable tannin extracts are heterogeneous mixtures of components with varying solubility.  
4.3 The solubility of such extracts is influenced by temperature and concentration, which affect the degree of dispersion and size of the component particles.  
4.4 While the solubility is better in hot water than in cold water, it is appropriate to dissolve and disperse an extract in hot water and then let the solution cool slowly to standard room temperature.
SCOPE
1.1 This practice covers the preparation of a solution of liquid extract that is to be used in the tannin analysis of that extract.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method is useful for determining the solid residue in analytical solutions.  
4.2 Because of the possibility of unknown errors in this test method, it is essential that the procedure be followed exactly in order to obtain reproducible results, both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method covers a procedure for the evaporating and drying of the 100 mL portions of analytical solution obtained in the methods for vegetable tannin analysis, so that consistent results may be obtained for the determination of total solids, soluble solids, and non-tannins in the sample. This test method is also intended for use in determining the moisture in the hide powder samples and the moisture in raw and spent materials in the methods for vegetable tannin analysis.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method gives the amount of ash remaining in the specimen after water extraction to remove water solubles from the leather in accordance with Test Method D2876. The insoluble ash is used in calculating the combined tannin because it is part of the tanned fiber structure that does not leach from the leather during water extraction.
SCOPE
1.1 This test method covers the determination of the insoluble ash in all types of vegetable-tanned leathers. This test method does not apply to wet blue.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method is useful to detect possible adulteration of tanning material extract with cheap and inferior lignosulfonates.
SCOPE
1.1 This test method is intended for use in detecting the presence of lignosulfonates (sulfite cellulose) in extracts of tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This practice provides a standard procedure for obtaining the water-soluble materials (including tannins) from any material that can be prepared for and charged to the steam-jacketed extractor. The extraction solutions are then analyzed according to Test Methods D4903, D6401, and D6402.
SCOPE
1.1 This practice covers extracting the tannin from raw and spent materials. The water extract obtained by this method is used to determine the tannin content of the original material. Analysis for total solids, soluble solids, and soluble non-tannins of the water extract from a material provides the information necessary to calculate the extractable tannin content of that material. The types of materials typically analyzed by this practice are products of plants such as woods, barks, leaves, nuts, fruits, roots, etc. and any of a wide variety of by-products (spent materials) from industrial processes utilizing plant products.  
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This practice provides standard procedures for obtaining representative samples of various materials used as a source of tannins for the tanning industry.  
5.2 Procedures are described for obtaining representative samples of economical and convenient quantities from a lot, or sections of a lot, of material for examination and analysis so that agreement may be reached with regard to the extent of variation of quality in different portions of a lot and the average quality of the entire lot of material.  
5.3 No directions for sampling, however explicit, can take the place of judgment, skill, and previous experience on the part of persons actually engaged in the sampling or the supervision of the sampling. These directions are intended to supplement that experience and, particularly, to serve as a guide in the selection of the method which is to be used, in common, by each of two or more contracting parties.  
5.4 Tanning materials contain moisture in varying amounts, depending both on the nature of the material and on the climatic conditions, so that sampling must be carried out as quickly as is consistent with thoroughness in order to avoid changes in moisture content.
SCOPE
1.1 This practice covers obtaining representative samples from shipment lots of botanical materials containing tannin.  
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the chemical properties of tannery liquors which are relevant for the vegetable tanning process and influence the astringency of vegetable tanning liquors. The astringency of liquors is dependent upon the solids and tannin content and the acidity. This method provides a standard procedure for determining these properties for any sample of vegetable tanning liquor.  
5.2 The specimens are aliquots from the analytical solution prepared from the sample of tannery liquor collected for this purpose.  
5.3 The total solids, soluble solids, and non-tannins content are determined and then the tannin content of the liquor sample is calculated. Because the amount of tannin per liter of analytical solution is less than that required for Test Method D6401, a table specifying the quantity of prepared hide powder to be used for solutions with lower tannin concentrations is included in this test method.  
5.4 The total acidity of the liquor sample is determined by one of two titrametric procedures described in Test Method D6410.  
5.5 The results of this test method are dependent on a great many variables but particularly upon: the temperature conditions under which the solutions were prepared and stored and the temperature at which the current analysis is performed; the uniformity and consistency of the Kaolin paste layer deposited onto the filter paper; the rate of solution run-out from the pipette; conditions related to the properties of the hide powder used to react with the tannin content of the solution; etc. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method covers the analysis of tannery liquors made up from vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the quantity of sugar present in vegetable tanning materials or vegetable tannin extracts. The amount of the reducing sugars, total sugars, and non-reducing sugars in a sample of material or extract can be determined by this method.  
5.2 Because of the possibility of errors in this test method it is essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method covers determining the sugars present in vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is used to determine one of the chemical properties of tannery liquors which are relevant for the vegetable tanning process and influence the astringency of vegetable tanning liquors. The astringency of liquors is dependent upon the solids and tannin content and the acidity. This test method provides a standard procedure for determining the total acidity for any sample of vegetable tanning liquor.  
5.2 The specimens are aliquots from the analytical solution prepared from the sample of tannery liquor collected for this purpose.  
5.3 The total acidity of the liquor sample is determined by one of two titrametric procedures described in this test method.
SCOPE
1.1 This test method covers determining the acidity of tannery liquors made up from vegetable tanning materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the moisture content of materials (raw or spent) that are to be extracted for tannin analysis. The value obtained for moisture content by this test method is used to calculate the results of the other analyses on this material to a moisture-free basis.  
5.2 The specimens are obtained from the material prepared for extraction in Practice D6405.  
5.3 Tanning materials contain moisture in varying amounts, depending both on the nature of the material and on the climatic conditions, therefore sampling must be carried out as quickly as is consistent with thoroughness in order to avoid changes in moisture content.  
5.4 Negative errors may occur in the moisture determination because under the conditions of this method there may be retention of moisture by certain components (for example, hydrated salts or water bound to organic structures) of the raw or spent material or because of oxidation of other components (for example, tannins) of the raw or spent material.  
5.5 Positive errors may occur in the moisture determination because under the conditions of this test method there may be volatilization of certain components of the raw or spent material other than water.  
5.6 It is known that other factors can also affect the quantity of volatile matter (moisture) released by the specimen. These factors include but are not limited to: particle size of the test specimen, quantity of test specimen, oven temperature, exposure time in the oven, shape of the specimen container, and type of oven (for example, gravity or mechanical convection) used.  
5.7 Because of the possibility of unknown errors in this test method it is essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining the moisture content in raw and spent materials that are extracted for tannin analysis. The moisture content of the sample is operationally defined to be equal to the weight loss experienced as a result of the evaporation which occurs in the drying oven.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This practice provides a standard procedure for comparing the color of leather tanned with different tanning extracts or mixtures of extracts or for monitoring the color consistency of tannery liquors.
SCOPE
1.1 This practice covers making color tests of all types of vegetable tanning extracts and of vegetable tanning materials to determine the color imparted to tanned skins.  
1.2 The values given in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is used to determine the proportion of the total solids which are soluble solids and that proportion which are insoluble solids in a solution of tannin extract or in the water extract from raw or spent materials prepared for tannin analysis.  
5.2 The specimens are aliquots from the analytical solutions prepared from tannin extracts or the water extract solutions prepared from raw or spent materials.  
5.3 The soluble solids are defined as the portion of the total solids which are dissolved in the water and pass through a filter prepared by depositing a layer of Kaolin paste onto a standard filter paper.  
5.4 The insolubles are defined as the portion of the total solids which do not pass through the standard filter paper prepared with the layer of Kaolin paste.  
5.5 The results of this test method are dependent on a great many variables but particularly upon:  
5.5.1 The temperature conditions under which the solutions were prepared and stored and the temperature at which the current analysis is performed;  
5.5.2 The uniformity and consistency of the Kaolin paste layer deposited onto the filter paper;  
5.5.3 The rate of solution run-out from the pipette; etc. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining the quantity of soluble solids and insolubles in solutions of tannin extracts, water extracts of vegetable tanning materials, or tanning liquors. This test method is applicable to the analysis of liquid, solid, pasty, and powdered tannin extracts and to the water extracts of raw or spent materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method is used to determine the quantity of iron and copper present in vegetable tanning materials or vegetable tannin extracts prepared using Practices D4901, D6404, or D6405.  
4.2 Because of the possibility of errors in this test method it is essential that the method be followed exactly in order to obtain reproducible results both among specimens within a laboratory and for analyses between laboratories.
SCOPE
1.1 This test method is intended for use in determining iron and copper content in vegetable tanning materials. This test method is applicable to liquid, solid, pasty and powdered extracts, to raw and spent materials, and to tannery liquors.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is designed to determine the cracking resistance of the grain or finish surface of leather on a pass/fail basis. This test method attempts to replicate the conditions that may be encountered by leather that is bent around a buckle frame or other anchoring device, folded over in seams or welts, and so forth. The cracking resistance of leather is influenced by many factors such as quantity, location, and type of fatliquoring materials; moisture content; thickness; the presence of defects or scar tissue, or both; the presence of processing damages to the skin or hide tissue; finish system formulation, and so forth. This test method is useful for manufacturing control in the tannery, specification acceptance, and quality control in the end product manufacturing plant.
SCOPE
1.1 This test method covers the determination of the resistance of leather to cracking when the leather is bent or folded with the grain (or finish) surface on the outside of the bend. Heavy leathers (for example, harness, belt, strap, bag, case, and so forth) are usually bent around a mandrel using either mechanical resistance (for example, clamp, vise, and so forth) or by hand. Lighter leathers (for example, shoe upper, upholstery, garment, glove, and so forth) are usually given a sharp double-fold (crosswise) bend after cooling to a low temperature. This test method does not apply to wet blue.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.