Blue Wool Scales are used to monitor the net exposure to light given to objects on display.
These scales are used to test for effects of light on textiles, paintings and documents with blue indicating scales.
Size of scale is : 127mm x 51mm
Each textile card encloses features of wool cloth dyed with blue dyes of different degrees of fastness which are used as light fastness standards. The blue wool card allows you to monitor the net exposure to light given to objects on display. it is also to alert conservators and their colleagues to adjust the intensity of illumination.