ASTM D7298-06

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Designation:D7298–06
Standard Test Method for
Measurement of Comparative Legibility by Means of
Polarizing Filter Instrumentation
This standard is issued under the fixed designation D7298; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2.3.1 Discussion—At 0° rotation, the analyzer and polar-
izer optical axes are perpendicular to one another.
1.1 This test method provides an objective means to com-
3.2.4 easel—located on top of the moveable stage; it is a
paratively measure the ease of reading printed matter for use in
platform where printed matter is placed to be read (see Fig. 1
package labeling.
and Fig. 2).
1.2 Thistestmethodisnotintendedtoquantifythelegibility
3.2.5 hand crank—a crank located at the front of the
ofaprinteditemagainstastandardbuttocompareitslegibility
instrument that adjusts the distance of printed matter by
against other items.
moving the stage and easel. When it is rotated counter
1.3 This test method uses human subjects to view printed
clockwise, it moves the moveable stage closer to the subject,
matter mounted in a specialized instrument.
and when it is rotated counterclockwise it moves the stage
1.4 The user of this test method must be aware that results
away from the subject (see Fig. 1 and Fig. 2).
may differ from one age group of subjects to another.
3.2.6 hand wheel—the wheel subjects turn to rotate the
1.5 This standard does not purport to address all of the
analyzer. Counterclockwise rotation increases the light trans-
safety concerns, if any, associated with its use. It is the
mitted and raises the legibility index. Clockwise rotation
responsibility of the user of this standard to establish appro-
decreases the light transmitted (see Fig. 1 and Fig. 2) and
priate safety and health practices and determine the applica-
lowers the legibility index.
bility of regulatory limitations prior to use.
3.2.7 legibility—the ease of deciphering or reading printed
2. Referenced Documents matter, as measured by the legibility index in this test method.
3.2.8 legibility index—the name given to the degrees of
2.1 ASTM Standards:
rotation of the analyzer, the reporting unit for the measurement
D996 Terminology of Packaging and Distribution Environ-
of legibility. The first point where the printed matter becomes
ments
easy forthe subject to read.
3. Terminology
3.2.9 moveable stage—a device topped with an easel that is
mounted on a track within the legibility instrument that adjusts
3.1 Definitions—Terms and definitions used in this test
the distance between the subject and the easel.
method may be found in Terminology D996.
3.2.10 polarizer—a fixed polarizing filter, mounted in the
3.2 Definitions of Terms Specific to This Standard:
instrument (see Fig. 1 and Fig. 2).
3.2.1 age group—subjects are grouped by ages in a speci-
3.2.11 subject—the person viewing the printed matter in the
fied range.
instrument and controlling the rotation of the analyzer.
3.2.2 analyzer—a moveable polarizing filter; the subject
3.2.12 tester—the person conducting the experiment.
operatesahandwheeltorotatetheanalyzer(seeFig.1andFig.
3.2.13 training reference—A standard message created in
2).
an8pointfont.Subjectsviewthetrainingreferencebeforedata
3.2.3 degrees of rotation—the angle of rotation of the
collection begins so that they become accustomed to the
analyzer where 0 is equivalent to no light transmission and 90
instrument without affectingtest results.
is equivalent to full light transmission.
4. Summary of Test Method
This test method is under the jurisdiction of ASTM Committee D10 on
4.1 This test method describes a means for evaluating the
Packaging and is the direct responsibility of Subcommittee D10.32 on Consumer,
legibility of printed matter such as package labeling, printed
Pharmaceutical and Medical Packaging.
inserts, and carton graphics by defining a standard procedure
Current edition approved Oct. 1, 2006. Published November 2006. DOI:
10.1520/D7298-06.
for measuring the comparative legibility of printed matter
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
under consistent, controlled light conditions by the use of a
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
specialized instrument.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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D7298–06
NOTE—*Analyzerandpolarizerareactuallyjustinsidethefrontwalloftheinstrument;subjectlooksthroughthemusingashieldedeyepiece(Seephoto
in Fig. 2). They are shown in the schematic to give researchers a clear idea of the instrument’s construction.
FIG. 1 Schematic of the Legibility Instrument
FIG. 2 Photo of Legibility Instrument
5. Significance and Use
5.1 This test method assists in evaluating the effect of
layout, typeface, type size, color, and background on the
legibility of printed matter.
D7298–06
5.2 Previous research has shown that results are more 7.2 Analyzer rotation measurement (readout of legibility
significantly impacted by subject age than any other effect. index), having a sensitivity of 0.1°.
Older subjects tend to require more light when using this 7.3 Rheostat, capable of providing minimum or maximum
instrument. Because subjects age at different rates as a result of light intensity.
lifestyle and genetics, variability of data tends to increase with 7.4 Built-in light sensor (readout of light level), a digital
increasing age. This test method was developed using subjects readout instrument capable of measuring light levels to 0.1 fc.
of ages 19 to 28 years. It is advised that subjects age 19 to 28 7.5 Stage distance, measurable to an accuracy of 61cm
be used in cases where variability needs to be kept to a (0.4 in.).
minimum.
8. Procedure
5.3 Testers can compare legibility between various groups
of subjects (by age, light intensity, distance, vision character-
8.1 Using the hand crank, the tester adjusts the moveable
isticsofthesubjects)andoneagainstotherlabelconfigurations stage so that the distance from the easel to the subject’s eyes
within groups of subjects
falls between 16 in. (41 cm) and 20 in. (51 cm).
8.2 The tester shall measure and record the visual acuity of
6. Apparatus
the subject, using a near distance visual acuity card with the
4 5
6.1 The legibility instrument (see Fig. 1 and Fig. 22) is a Snellen visual acuity scale.
rectangular structure designed to minimize light leakage and to 8.3 The tester shall record the subject’s gender and age
provide an internal platform to hold printed matter to be tested. 8.4 The tester rotates the analyzer to a position of 0° of
6.2 The interior shall have a gray or black matte surface to rotation (so that no light passes through).
minimize internal light reflection.
8.5 With the door of the instrument closed, the rheostat is
6.3 An end panel shall have a polarizer and an analyzer used by the tester to adjust the light level inside the instrument
mounted in its center, controlled by a hand wheel (see Fig. 1).
to 25 6 1 fc.
6.4 The analyzer is capable of being rotated to a maximum 8.6 The tester places the training reference onto the easel.
of 90° (relative to the polarizer).This rotation allows the filters
8.6.1 The reference should be flat against the easel and not
to go from total light blockage to full light tra
...