The Journal of the Board of Arts and Manufactures for Upper Canada, April 1867
M. Neipce de St. Victor has recently communicated to the French Academic des Sciences the results ofhis latest researches, having for their object to obtain and fix the colors of nature by means of photography. His paper is full of very important, new and interesting facts, proving that the fixation of natural colors on the photographic tablet as a practicable and available result, which for a long time has been considered as a dream, is not perhaps so far from being fully realized — not as a mere scientific experiment, but as the completion of the splendid discovery of photography.
The process of M. Niepcede St. Victor may be shortly described as follows: - The silver plate must first be chlorurised, and then dipped into a bath containing fifty centigrammes of an alcoholic solution of soda for every 100 grammes of water, to which a small quantity of chloride of sodium is then added. The temperature of the bath is raised to about sixty degrees centigrade, and than the plate is only left in for a few seconds, the liquid being stirred all the time. The plate being taken out, it is rinsed in water and then warmed until it acquires a bluish-violet bus, which is probably produced by the reduction of a small quantity of chloride of silver. The plate is now coated with a varnish composed of dextrine and chloride of lead. In this way all the colors of the original, including white or black of more or less intensity, are reproduced, according as the plate has been prepared, and as the blacks of the copy are either dull or brilliant. The reduction of the chloride should not be too great, because otherwise nothing but pure black or pure white could be obtained; and in order to avoid this inconvenience a little chloride of sodium is added to the soda bath. A few drops of ammonia will produce the same effect. By this process a colored drawing, representing a French guardsman, was reproduced by M. Niepce, with the exception of one of the black gaiters, which he had cut and replaced with white paper. The black hat and the other gaiter produced a strong impression on the plate, while the white gaiter was perlectly reproduced in white. Much more intense blacks may be obtained by previously reducing the stratum of chloride of silver by the action of light; but then all the other colors lose the brilliancy in proportion.
This production of black and white is a considerable step in heliochomy. It is a most curious and interesting fact, for it would prove that black is not entirely the absence of light, but is a color of itself, producing its own effects, as well as the other colors. This was illustrated by the experiment made at the suggestion of M. Chevreul, the celebrated member of the Académie des Sciences whose known researches on the contrast and effect of colors are so instructive and interesting. Accordingly, M. Neipce tried to represent on his plate the black pro used by the absepce of light in a hollow tube. But the hole produced no effect, or rather it was negative, which is not the case when the black of natural objects, represented in a colored picture reflects its own tints, or, if we may say so, its own rays — endowed it would appear, like all others, with chemical action, for the apparent reason that the hole could not reflect any rays, and its blackness is the result only of the absence of all rays. The same thing may be said of the white, but less extraordinarily; for the white being the result of the rays united, it may be more easily understood that the chemical action of the white would be the compound result of the various rays of which it is composed, and that result is the same as that whichgives us the sensation of white. Certainly the reproduction of black and white by M. Niepce de St. Victor is a most extra ordinary fact unfolded by his beautiful discovery, and perhaps more surprising than the reproduction of all the colors themselves.
It is not possible at present to foresee all the consequences of the researches of M. Neipce de St. Victor. It may be the seed that in the field of science will, by proper cultivation, grow into a gigantic tree, from which time will probably reap the most nutritious and wonderful fruits.
- British Journal of Photography
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