Blue Scale is used to test colour fastness of cloths or leather exposed to light, in according with:
The Blue Scale is a card with 8 sticked blue scale gradations in pure wool, which allows to determine the resistance of the color of fabrics or leathers to the action of an artificial light source (Xenon lamp, Xenotest or Sunlight Test).
The value of the light fastness depending on the type of fabric / leather and the quantity of the pigment used.
To verify the light fastness needs to compare the fabric / leather with the tonality of the blue standards.
The values present in the blue scale start from the lowest (1 = low solidity) to the highest (8 = maximum solidity).
Dimensions: 25 X15 cm