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An Improved Colour‐difference Formula for use in Light‐fastness Testing
Author(s) -
Vaeck S. V.
Publication year - 1978
Publication title -
journal of the society of dyers and colourists
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 49
eISSN - 1478-4408
pISSN - 0037-9859
DOI - 10.1111/j.1478-4408.1978.tb00021.x
Subject(s) - grey scale , chromaticity , mathematics , lightness , colour difference , color difference , scale (ratio) , statistics , significant difference , optics , artificial intelligence , computer science , physics , enhanced data rates for gsm evolution , quantum mechanics
An analysis is made of data obtained in a comparison of the colour differences between faded and unfaded Blue light‐fastness standards with Grey Scale steps, which showed that the ANLAB and CIELAB formulae result in colour differences up to four times greater for the Blue standards than for visually equivalent Grey Scale steps. It is shown that this is due to an underweighting of the lightness difference against the chromaticity difference by a factor which depends on the relative amounts of each difference component. A formula is proposed which shows a near‐perfect correlation with the experimental data and thus mades it possible to measure the degree of fading of any Blue standard in Grey Scale steps. When this formula is tested against the Morley data, which are based on perceptibility testing, the correlation is worse than for the ANLAB or the CIELAB formulae. The reasons for this apparent contradiction are discussed.