Journal . coulciirs. Paris. 1878- 1 Brevet, 162,645, December 18,1882 ; Kng. Pat 101, 1883. *i Sii/unKFib. d. kais. Akad. der Wisscnsch. Wien. II. Abth,1881; 11. Abth, 1885 ; and II. Abth, 1880. ) THE JOURNAL OF THE SOCIETY OF CHEMICAL INDUSTRY. 425 tinguish between the effect of a dye on the generalsensitiveness of a plate to light as a whole, and on itsrelative sensitiveness to particular rays. The majorityof dyes render the plates less sensitive to ultra-violet,violet, and, in several cases, blue rays, and thusdiminish their general sensitiveness to one-fifth, oreven one-tenth,
Journal . coulciirs. Paris. 1878- 1 Brevet, 162,645, December 18,1882 ; Kng. Pat 101, 1883. *i Sii/unKFib. d. kais. Akad. der Wisscnsch. Wien. II. Abth,1881; 11. Abth, 1885 ; and II. Abth, 1880. ) THE JOURNAL OF THE SOCIETY OF CHEMICAL INDUSTRY. 425 tinguish between the effect of a dye on the generalsensitiveness of a plate to light as a whole, and on itsrelative sensitiveness to particular rays. The majorityof dyes render the plates less sensitive to ultra-violet,violet, and, in several cases, blue rays, and thusdiminish their general sensitiveness to one-fifth, oreven one-tenth, of its original value, whilst at thesame time the relative sensitiveness to particularsays, such a yellow, orange, or green, may beincreased many times.* The results are representedin the form of curves. Violet dyes, such as Hofmanns violet, gentianviolet, methyl violet, acid violet, diminish the generalsensitiveness, mainly by making the plate much lesssensitive to ultra violet rays. At the same time the. Fig. 2. (II Violets. (2l Greens. (3) Iodine Green. (1) Cyanin, (51 Eosin.(61 Rose Bengal - Ammonia. 171 Ccerulein. (8> Chrysaniline.(9i Eosin and Silver Chloride, (10) Eosin + Cyanin. sensitiveness to green, yellow, and orange is consider-ably increased, the maximum effect being observedbetween D and C. (Fig. 2, No. 1.) Green dyes, such as acid green, benzaldebydegreen, ethyl green, methyl green, and their varieties,have very little sensitising action, and their effect canonly be observed with prolonged exposure and bril-liant illumination, great attention being paid to theproper regulation of the proportion of dye. Underfavourable conditions the plate is made slightly sensitive to yellow, orange and red, the point of maximumeffect being situated close to the line C. (Fig. 2, No. 2.)Iodine green is worthy of notice, since its sensitisingaction, although feeble, extends to the extreme red.(Fig. 2, No. 3.) In this respect, however, it is farinferior to certain dyes which we
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
