Blue scale light fastness type 1, 25 x 15 cm
With this type 1 test sheet the effect of light on paintings, documents and textiles can be determined. The sheet can be cut to the desired size. One half necessarily for comparison with aluminum foil or similar. Mask off!
The blue scale is a measure of the light fastness of organic materials and a vivid dosimeter for convincing museum directors or exhibition makers.
The following table gives an overview of the evaluation of the blue scale, where column A indicates the number of the test strip and column B the approximate number of megalux hours, which leads to a first perceptible discoloration. Since the type of lighting is not specified, the description of megalux hours is to be understood only as a rough guide.
Blue wool / ASTM lightfastness standards | ||
A | B | Comments |
8th | 900 | I. Excellent lightfastness. Blue wool 7-8. The pigment will remain unchanged for more than 100 years of light exposure with proper mounting and display. |
7 | 300 | |
6 | 100 | II. Very good lightfastness. Blue wool 6. The pigment will remain unchanged for 50 to 100 years of light exposure with proper mounting and display. |
5 | 32 | III. Fair lightfastness (impermanent). Blue wool 4-5. The pigment will remain unchanged for 15 to 50 years with proper mounting and display. |
4 | 10 | |
3 | 3.6 | IV. Poor lightfastness (Fugitive). Blue wool 2-3. The pigment begins to fade in 2 to 15 years, even with proper mounting and display. |
2 | 1.3 | |
1 | 0.4 | V. Very poor lightfastness (Fugitive). Blue wool 1. The pigment begins to fade in 2 years or less, even with proper mounting and display. |
A : Blue wool reference strip |
Material | dyed cotton |
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Dimensions | 15 x 25 cm |