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Tinted Lens 71

Violet: Violet is the least chosen tint of all. It is almost as photoactive as
ultraviolet and can irritate eyes and even cause eye damage.

METHODS OF LENS TINTING
A spectacle lens is said to be tinted if the transmission of light is deliberately
decreased by any means, either over the whole of the visible spectrum and
its neighbouring regions, or merely a part of it. They offer selective
absorption for each wavelengths of the spectrum, and this determines their
tints. Such absorption may be fixed or variable. Fixed absorption is the
case with all traditional fixed tinted glasses, whereas, photochromic glasses
offer variable absorption where transparency varies according to light
conditions.

Fig. 7.6: Types of tinted lens

Colour results from the absorbent properties of glasses in the visible
spectrum. The body will have the colour of the part of the spectrum in
which it is placed.

Fig. 7.7: Colour wheel