DIN EN 20105-A02 Scale for Colour Change (accredited)

Our test laboratory performs testing according to DIN EN 20105-A02 using an accredited test method for the visual assessment of colour change using the grey scale. The method is used to provide a standardized assessment of changes in the colour of a material resulting from exposure or a colour fastness test. For this purpose, the colour difference between the original and tested material is compared with defined grey-scale contrasts and expressed as a fastness rating. This allows colour changes to be assessed consistently, irrespective of the specific cause of the exposure.

Test procedure

For the test, the original material and the specimen subjected to a defined exposure are placed side by side and assessed under specified lighting and viewing conditions. The visible colour difference is compared with the grey scale, whose individual steps represent defined differences in contrast.

The assessment is expressed as fastness ratings from 5 to 1, with grade 5 indicating no or only a very slight visible colour change and grade 1 indicating a very strong colour change. For a more differentiated assessment, the intermediate grades 4–5, 3–4, 2–3 and 1–2 may also be used. If required, the nature of the colour change, for example a shift in hue, can also be described.

Applications of the test

DIN EN 20105-A02 is used for the assessment of colour changes following a wide range of colour fastness, ageing and resistance tests. The grey scale does not itself impose any stress on the material, but serves as a standardized assessment method for colour changes caused by a preceding exposure. This enables test results from different materials, treatments and exposure conditions to be classified consistently and compared with one another.

Typical test materials and applications include:

• textiles and yarns,

• artificial leather and coated textiles,

• leather and leather fibre materials,

• plastics, elastomers and films,

• upholstery and covering materials,

• materials for vehicle interiors,

• clothing and footwear materials,

• surfaces after exposure to light, rubbing, water, perspiration or ageing,

• materials used for comparative assessment of formulations, dyeings and surface treatments.

The method is particularly important wherever colour changes following a defined exposure need to be assessed reproducibly and consistently. The grey scale provides a standardized visual classification and is therefore used as an assessment tool in numerous test methods for colour fastness and material resistance.

Related tests

As a directly related test, FILK also offers DIN EN ISO 105-A05, in which the change in colour is assessed instrumentally and converted into a grey-scale rating. DIN EN ISO 105-A03 uses a grey scale for the visual assessment of staining on adjacent fabrics. DIN EN ISO 105-A04 additionally provides an instrumental method for assessing staining.