ISO 17223:2026

International
Standard
ISO 17223
Second edition
Plastics — Determination of
2026-04
yellowness index and change in
yellowness index
Plastiques — Détermination de l'indice de jaunissement et du
changement de l'indice de jaunissement
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Preparation and conditioning of samples and test specimens . 2
4.1 Sample and preparation of test specimen .2
4.2 Conditioning of test specimen .2
4.3 Environment of measurement condition .2
5 Procedure . 2
5.1 General .2
5.2 Transmission measurement method for sheet, film, moulded plaque, or disc specimens .3
5.3 Reflection measurement method for sheet or film specimens .3
5.4 Reflection measurement method for pellet or powder specimens .3
5.5 Measurement requirements .4
5.5.1 Sheet, film, moulded plaque, or disc specimen .4
5.5.2 Pellet or powder specimen .5
6 Expression of results . 5
6.1 Calculation procedure of yellowness index .5
6.2 Calculation procedure of change of yellowness index .5
6.3 Precision . . .5
6.3.1 Precision of film and sheet specimen .5
6.3.2 Precision of pellet and powder specimen .9
7 Test report . 9
Bibliography .10

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Foreword
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This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
This second edition cancels and replaces the first edition (ISO 17223:2014), which has been technically
revised.
The main changes are as follows:
— new terms (3.3 and 3.4) have been added;
— measurement environment conditions have been adapted (see 4.3), and conditioning of test specimens
(see 4.2) has been added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

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International Standard ISO 17223:2026(en)
Plastics — Determination of yellowness index and change in
yellowness index
1 Scope
This document specifies an instrumental method for determining the yellowness index and change in
yellowness index on clear, translucent, or opaque plastics.
NOTE Change in yellowness index is often used to evaluate the effect of environment, e.g. heat, UV exposure, etc.,
on colour stability.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 291, Plastics — Standard atmospheres for conditioning and testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
yellowness index
Y
I
deviation in chroma from colourless or whiteness toward yellow
3.2
change of yellowness index
ΔY
I
difference between yellowness index of specimen before additional test and yellowness index of specimen
after additional test
Note 1 to entry: For example, before and after exposure to specified conditions.
3.3
integrating sphere
optical component consisting of a hollow spherical cavity with an inner surface that is covered with a diffuse
white reflective coating
3.4
optical geometry
method and angle of incidence of light on the test piece, the method and angle of incidence of light on the
light receiver, and combinations of these.
Note 1 to entry: There are two methods of incidence: parallel light incidence and diffuse light incidence.

4 Preparation and conditioning of samples and test specimens
4.1 Sample and preparation of test specimen
Specimen shapes can include moulded plaques or discs, films, sheets, powders, and pellets. Plaque, disc, film,
and sheet specimens can have smooth, matt, or patterned surfaces. Fluorescent plastics are not permitted.
Samples shall be gathered by a statistical method from the batch to be evaluated. In all cases, the sample
shall be used as received unless the purpose is to evaluate pellets or powders converted into a final shape,
i.e. moulded plaques or discs, films, or sheets.
4.2 Conditioning of test specimen
Before the test, if there is no relevant standard, the conditioning of test specimen shall be carried out at
(23 ± 2) °C and (50 ± 10) % RH according to ISO 291.
4.3 Environment of measurement condition
Set up the test apparatus in an atmosphere maintained at (23 ± 2) °C and (50 ± 10) % RH.
5 Procedure
5.1 General
Colourimetry is derived from calculating tristimulus values by spectral or tristimulus measurements. In the
case of the specimen with the diffusibility of the light, the measuring apparatus shall have an integrating
sphere or other system that can detect diffusion light. Optical geometries, requirements, and solution for
different measurement methods are given in Table 1.
Table 1 — Optical geometries, requirements, and solution for different measurement methods
Measurement method Optical geometries Requirements Solution
in accordance with
CIE
...