In 1913, Crookes created an ultraviolet blocking lens made from glass containing cerium, but only lightly tinted. They were an unintended by-product of Crookes's research to find a lens glass formulation that would protect glass workers from cataracts. Crookes tested more than 300 formulations, NIST each numbered and labelled. Crookes Glass 246 was the tint recommended for glassworkers. The best-known Crookes tints are A (withdrawn due to its uranium), A1, B, and B2, which absorb all ultraviolet below 350 nm while darkening visual light. Crookes's samples were made by Whitefriars, London, stained glass makers, and Chance Brothers, Birmingham.
In 1913 Crookes created an ultraviolet blocking lens made from glass containing cerium but only lightly tinted They were an unintended by-product of Crookes's research to find a lens glass formulation that would protect glass workers from cataracts Crookes tested more than 300 formulations NIST each numbered and labelled Crookes Glass 246 was the tint recommended for glassworkers The best-known Crookes tints are A (withdrawn due to its uranium) A1 B and B2 which absorb all ultraviolet below 350 nm while darkening visual light Crookes's samples were made by Whitefriars London stained glass makers and Chance Brothers Birmingham