Tinted trial lenses

The trial lenses are tinted with one of seven dyes, providing seven colours. There are 5 trial lenses of each colour (6 in the case of rose and purple). These trial lenses form a series with increasing degrees of dye deposition. The deposition increases from one trial lens to the next in the series. Any trial lens has twice as much pigment as its lighter neighbour in the series, and half as much pigment as its darker neighbour. The trial lenses can be superimposed one upon another. Thirty one (2 to the power 5 less one) combinations of five lenses are possible. These combinations provide 31 small and equal steps of dye deposition ranging from saturation that is so weak as to be barely noticeable to saturation so strong as to be very dark. The 31 combinations of one colour can be combined with the 31 of a neighbouring colour so as to provide 961 possible combinations of the two, with various shades between the two colours. Taking the combinations of pairs of neighbouring colours in the diagram below is sufficient to fill the gamut shown in the central CIE UCS diagram. In other words, it is possible to obtain virtually any colour with a high degree of precision simply by combining trial lenses of neighbouring colours - e.g. rose and orange, orange and yellow, yellow and green etc.  Complementary colours are never combined, and this ensures that the transmission is as high as possible, given the colour.

The combination of trial lenses necessary to match any given setting of the Intuitive Colorimeter Mark2 and 3 can be obtained by a computer program that is available for downloading..




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