HIGHLY-TRAINED EYES

Otago Daily Times, Issue 22830, 14 March 1936, Page 14

HIGHLY-TRAINED EYES

In the modern rainbow laboratory there are men whose highly-trained eyes can detect over 300 shades of white and nearly as many kinds of blacks. Such a rainbow laboratory (states a writer in Popular Science) exists in Delaware, where a staff of highly-trained scientists and technical workers spent their time developing new dyes. These colour scientists work with highly specialised instruments —with spect'ro-photometers for measuring the wavelength of light 'reflected or transmitted by a dye; with artificial weather machines which subject dyed material in a few hours to as severe weathering as it normally would receive in months or years; with sensitive balances for weighing out exact quantities of dyes and test fabric or thread. But the most important job in the laboratory—the matching of colours to determine whether they come l.p to standard—is done with the human eye. Machines have been produced that are as sensitive to colour differences as the human eye, in that they measure the stimulus we know as colour with equal delicacy. But these machines do not trivo their readings in terms of physiological response, which, after all, is the chief thing about colour that interests us. A well-trained eye, according to the director of the laboratory, can recognise something like 100,000 different hues and colours. If, to a batch of yellow dye, one twentythousandth as much red dye as yellow is added, such an eye can detect it!