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A new photographic process without metallic salts
Dec., 189°']
C]zemical SectioJz.
485
A NEW P H O T O G R A P H I C PROCESS WITHOUT M E T A L L I C SALTS.
This process was presented at the recent meeting of the British Association for the A d v a n c e m e n t of Science, by Mr. A. G. Green, and his co-laborers, Messrs. Cross and Bevan, in a paper detailing highly successful experiments with primuline for producing designs on cotton, linen or silk cloths, on papcr, and, by aid of gelatine, on glass, etc., by a ,,photographic m e t h o d of dyeing and printing." T h e process requires no longer time of exposure than that with silver salts, whilst it has a more general range of sensitiveness in the spectrum, and at the same time affords the choice of a great variety of colors for the finished prints: .and as primuline is a commercial article used on a large scale, it is comparatively inexpensive. The process will 0nly be outlined in brief. Primnline, a coal-tar product, is an amido-sulphonJc acid discovered by Mr. Green, in I887, and named by reason of the primrose yellow color imparted by it to cotton in alkaline solution, without a mordant. It has been quite extensively used for producing a great variety of colors in cotton cloth by dia~off~ing the compound in the cloth dyed with primutine, by passing it through a weak solution of nitrous acid, or rather of a nitrite with an acid, and thus i m p a r t i n g to it the property of combinin K with various phenols or amines to produce in the fabric a variety of highly colored, very fast dyes the so-called ingrain colors, the particular color ii~ any case being determined by the phenol or amine employed in solution rendered acid or alkaline as may be necessary. It was found that tile diazotized compound is extremely sensitive to light, which destroys this property of combining with the phenols and amines, so that a fabric dyed with primuline, then washed and treated with nitrite of soda and acetic acid, and again washed, and then exposed, either moist or dry under any design, as a drawing or a negative, will lose
486
6)}e,zica/ 5cclz))n.
[ J. F. 1.,
the p r o p e r t y of b e c o m i n g dyed b y the phenols and amines in the parts acted upon by light, so that in a s u b s e q u e n t t r e a t m e n t with a s u i t a b l e amine or phenol, as a developer, only the protected parts will b e c o m e dyed, and a prin t will be producc
C]zemical SectioJz.
485
A NEW P H O T O G R A P H I C PROCESS WITHOUT M E T A L L I C SALTS.
This process was presented at the recent meeting of the British Association for the A d v a n c e m e n t of Science, by Mr. A. G. Green, and his co-laborers, Messrs. Cross and Bevan, in a paper detailing highly successful experiments with primuline for producing designs on cotton, linen or silk cloths, on papcr, and, by aid of gelatine, on glass, etc., by a ,,photographic m e t h o d of dyeing and printing." T h e process requires no longer time of exposure than that with silver salts, whilst it has a more general range of sensitiveness in the spectrum, and at the same time affords the choice of a great variety of colors for the finished prints: .and as primuline is a commercial article used on a large scale, it is comparatively inexpensive. The process will 0nly be outlined in brief. Primnline, a coal-tar product, is an amido-sulphonJc acid discovered by Mr. Green, in I887, and named by reason of the primrose yellow color imparted by it to cotton in alkaline solution, without a mordant. It has been quite extensively used for producing a great variety of colors in cotton cloth by dia~off~ing the compound in the cloth dyed with primutine, by passing it through a weak solution of nitrous acid, or rather of a nitrite with an acid, and thus i m p a r t i n g to it the property of combinin K with various phenols or amines to produce in the fabric a variety of highly colored, very fast dyes the so-called ingrain colors, the particular color ii~ any case being determined by the phenol or amine employed in solution rendered acid or alkaline as may be necessary. It was found that tile diazotized compound is extremely sensitive to light, which destroys this property of combining with the phenols and amines, so that a fabric dyed with primuline, then washed and treated with nitrite of soda and acetic acid, and again washed, and then exposed, either moist or dry under any design, as a drawing or a negative, will lose
486
6)}e,zica/ 5cclz))n.
[ J. F. 1.,
the p r o p e r t y of b e c o m i n g dyed b y the phenols and amines in the parts acted upon by light, so that in a s u b s e q u e n t t r e a t m e n t with a s u i t a b l e amine or phenol, as a developer, only the protected parts will b e c o m e dyed, and a prin t will be producc