COLOUR PHOTOGRAPHY.

New Zealand Herald, Volume XXXVII, Issue 11538, 24 November 1900, Page 5 (Supplement)

COLOUR PHOTOGRAPHY.

SIMPLICITY THE FEATURE OF THE NEW PROCESS. The specimens of colour photographs by the MeDonough-Joly process at the Royal Photographic Society's Exhibition at the New Gallery are exciting much attention. The secret of photographing colours has been long sought for, and it is claimed that at last the problem has been solved. Mr. C. N. Crewdson, a young, 'cute American, who is corresponding secretary of the Chicago Society of Egyptian Research, and has taken a large number of pictures in Egypt by the new process, told an Express representative something about it. Simplicity is its great charm. Based upon the "researches of Clerk-Maxwell and the Young-Hemholtz theory of the nature of light, the McDonough-Joly process consists of an ordinary piece of glass on which are ruled lines of the fundamental colours, red, green, and blue, in spectrum order, from three to five hundred to the inch. The secret of the invention lies in prepared glass or screen, and is protected by patent. Ordinary cameras can be fitted with the apparatus, which includes a yellow ray filter, to cut down the excessive chemical effect of the blue ray of light. The "exposure" is made in the ordinary way, but the time required is somewhat longer, because the light must pass through the tri-coloured screen and the ray filter. This is compensated for by using a plate which is exceedingly sensitive to Tight. The object photographed in this way has all its natural tints. One negative and one exposure are enough, and there is no need of brushes and " touching-up." The process can be utilised for magazine, book, and newspaper illustrations. A machine has just been erected in New York which is considered capable of turning out 24,000 copies of coloured illustrations per hour by this process. When first tried, it turned out 5000 in an hour without any failure. In ordinary three-colour work the loss is reckoned at 30 per cent., so the contrast is remarkable. There is romance and pathos in the story of this invention. Its essential features were discovered inI dependently and almost simultaneously by Dr. Joly, of Dublin, and Mr,. McDonough, an electrician, of Chicago. Mr. McDonough, whose friends claim that he is the real inventor of the telephone, gave 25 years to the subject of colour photography. Warned by his experience in having his labours on the telephone thrown away, he worked in secret. 111-health overcame him, fortune forsook him, but he stuck to his investigations. The first successful exposure was made only the day before he died; he never lived to see the perfect picture. Paralysis reduced him to a pitiable state in his last days; and he was obliged to call in others, who, after his death, continued the work to which he was so devoted..