Testing acc. to ISO 105-A05: Textiles - Tests for colour fastness - Part A05: Instrumental assessment of change in colour for determination of grey scale rating
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Our test laboratory performs testing according to DIN EN ISO 105-A05 as an accredited test method. The method is used for the instrumental assessment of colour changes resulting from a colour fastness test on a textile material. It provides an objective alternative to visual assessment using the grey scale.
The colour of the tested specimen is compared with an identical untreated reference specimen. The instrumentally determined colour difference is then converted into a grey scale rating for colour change.
Applications
DIN EN ISO 105-A05 is used in conjunction with colour fastness tests in which defined exposure may cause a colour change, for example through water, rubbing, perspiration, light, heat or other media.
The method is particularly suitable for objective and reproducible assessment of textiles and yarns in product development, quality control and comparative material testing. Differences between production batches, dyeings, prints or surface treatments can be quantified and converted into the established grey scale rating.
Testing according to DIN EN ISO 105-A05
Before and after the respective colour fastness exposure, an untreated reference specimen and the tested specimen are measured under defined conditions using a spectrophotometer or colorimeter.
The measured colour values are used to calculate changes in lightness, chroma and hue as well as a resulting colour difference. This colour difference is then converted into a grey scale rating for colour change.
The results correspond to the rating system used for visual colour fastness assessment. High ratings indicate little or no perceptible colour change, while lower ratings indicate progressively greater colour change.
Related tests
The general principles of colour fastness testing are described in the accredited DIN EN ISO 105-A01 – General principles of testing.
While DIN EN ISO 105-A05 instrumentally evaluates the colour change of the tested specimen, the accredited DIN EN ISO 105-A04 – Instrumental assessment of the degree of staining of adjacent fabrics is used to assess colour transfer to adjacent materials.
Instrumental assessment can also be combined with specific colour fastness tests such as DIN EN ISO 105-X12 – Colour fastness to rubbing or DIN EN ISO 105-B06 – Colour fastness and ageing to artificial light at high temperatures.
