The Action of Light upon Dyed Colours.-Report of the Committee, consisting of Professor T. E. THORPE (Chairman), Professor J. J. HUMMEL (Secretary), Dr. W. H. PERKIN, Professor W. J. RUSSELL, Captain W. DE W. ABNEY, Professor W. STROUD, and Professor R. MELDOLA. (Drawn up by the Secretary.) DURING the past year the work of this Committee has been continued, and a large number of wool and silk patterns, dyed with various natural and artificial orange and yellow colouring matters, have been examined with respect to their power of resisting the fading action of light. The general method of preparing the dyed patterns, and the manner of exposing them under glass, with free access of air and moisture, were the same as already adopted. The patterns were exposed at Adel, near Leeds, in the grounds of James A. Hirst, Esq., to whom the best thanks of the Committee are again due for his kind permission to do so. Each dyed pattern was divided into six pieces, one of which was protected from the action of light, while the others were exposed for different periods of time. These 'periods of exposure' were made equivalent to those adopted last year, by exposing, along with the patterns, special series of 'standards,' dyed with the same colouring matters as were then selected for this purpose. The standards were allowed to fade to the same extent as those which marked off the 'fading period of last year, before being renewed or removing a set of dyed patterns from the action of light. The patterns exposed during the past year are therefore comparable, in respect of the amount of fading which they have experienced, with the red dyes already reported upon. The patterns were all put out for exposure on June 8, 1893, certain sets being subsequently removed on the following dates :-July 1, July 31, August 26, 1893; February 19, June 12, 1894. Of the five 'periods of exposure' thus marked off, periods 1, 2, 3 were equivalent to each other in fading power, whereas periods 4 and 5 were each equivalent to four of the first period in this respect; hence five patterns of each colour have been submitted respectively to an amount of fading equal to 1, 2, 3, 7, and 11 times that of the first 'fading period' selected-viz. June 8 to July 1, 1893. The dyed and faded patterns have again been entered in pattern-card books in such a manner that they can be readily compared with each other. The following tables give the general result of the exposure experiments made during the year 1893-94, the colours being divided, according to their behaviour towards light, into the following five classes: very fugitive, fugitive, moderately fast, fast, very fast. The initial numbers refer to the order of the patterns in the patternbooks. The S. and J. numbers refer to Schultz and Julius's 'Tabellarische Uebersicht der künstlichen organischen Farbstoffen.' The colours marked thus (*) appear to be somewhat faster than the rest of the class in which they are placed. In the case of colouring matters requiring mordants, the particular mordant employed is indicated in brackets after the name of the dyestuff. CLASS I. VERY FUGITIVE COLOURS. (WOOL.) The colours of this class have faded so rapidly that at the end of the first fading period' (June 8 to July 1, 1893) only a very faint colour remains, or it has become very materially altered in hue. At the end of the fifth period (one year) all traces of the original colour have disappeared, the woollen cloth being either quite white or merely of a yellowish or brownish tint. Wool Book III. Nitro Colours. Acid Yellows. 9. Aurantia. Ammonium salt of hexa-nitro-diphenylamine. S. and J. 14. 32. *Brilliant Yellow. Sodium salt of dinitro-a-naphthol-a-sulphonic acid. S. and J. 12. 37. *Naphthol Yellow. Sodium salt of dinitro-a-naphthol. S. and J. 9. 38. *Naphthol Yellow S. Sodium salt of dinitro-a-naphthol-B-sulphonic acid. S. and J. 11. 43. Picric acid. Tri-nitro-phenol. S. and J. 1. Azo Colours. Mordant Colours. 14. *Wool Yellow (Cr.). From azo derivative of aniline and Basic Yellows. 4. Chrysoïdine. From aniline and m-phenylene-diamine. S. and naphthionic acid. 9 Direct Orange RR. Constitution not published. 26. Thiazol Yellow. From azo derivative of dehydro-thio-toluidinesulphonic acid, and dehydro-thio-toluidine-sulphonic acid. S. and J. 98. 28. Mimosa Yellow. From azo derivative of primulin, and ammonia. Constitution not published. Constitution not published. 39. Direct Yellow ASC. Constitution not published. Diphenylmethan Colours. Basic Colours. 7. Auramine. Imido-tetra-methyl-diamido-diphenyl-methan-hydro chloride. S. and J. 260. Triphenylmethan Colours. Acid Colours. 48. Uranin A. Sodium salt of fluoresceïn. S. and J. 315. Quinoline Colours. Basic Colours. 42. Quinoline Yellow (sol. in spirit). Quino-phthalone. S. and J. 378. Acridine Colours. 1. Acridine Orange R. extra. Zinc salt of tetra-methyl-diamidophenyl-acridine. 2. Acridine Orange NO. Zinc salt of tetra-methyl-diamido-acridine. S. and J. 381. 3. Phosphine. Diamido-phenyl-acridine-nitrate. S. and J. 382. " 6. Benzoflavine. Diamido-phenyl-di-methyl-acridine hydrochloride. S. and J. 383. Wool Book III. Thiobenzenyl Colours. Basic Colours. 9. Thioflavin T. Dimethyl-dehydro-thio-toluidine-methyl chloride. S. and J. 384. Acid Colour. 29. Thioflavin S. Sodium salt of dimethyl-dehydro-thio-toluidinesulphonic acid. S. and J. 385. Direct Cotton 31. Primulin. Sulphonated product of the interaction of sulphur and Colour. p-toluidine. S. and J. 386. Natural Colouring Matters. Non-mordant Colours. 1. Annatto. Pulp from fruit of Bixa orellana. 2. Saffron. Stigmata of the flower of Crocus sativus. Mordant Colours. 1. Young Fustic (Al.). Wood of Rhus cotinus. 39 NOTES.-Certain of the nitro colours show extreme sensitiveness to light by rapidly altering in hue. During the first 'period of exposure,' the rich red-orange colour of Aurantia, for example, soon changes to brown, and the pure lemon-yellow of Picric Acid changes to orange-yellow; in both cases these altered colours fade slowly without any further change in hue, and might almost be placed among the 'moderately fast colours.' Brilliant Yellow, Martius Yellow, and Naphthol Yellow S behave somewhat like Picric Acid, but the alteration in hue is much less pronounced. Thiazol Yellow, Mimosa Yellow, Thioflavin T and S, and Primulin all fade rapidly during the first 'period of exposure' to a yellow-buff, which then appears to be 'moderately fast.' CLASS II FUGITIVE COLOURS. (WOOL.) The colours of this class show very marked fading at the end of the second fading period' (July 1 to July 31, 1893), and after a year's exposure they have entirely faded, or only a tint remains. Wool Book III. Azo Colours. Acid Colours. 1. Orange R. From xylidine-sulphonic acid and B-naphthol. S. and J. 81. 6. Orange I. From p-sulphanilic acid and a-naphthol. S. and J. 72. 14. Narceïn. Sodium bisulphite compound of Orange II. S. and J. 103. 35. Phenoflavin. From m-sulphanilic acid and diamido-phenol-sulphonic acid. Direct Cotton 4. Benzo Orange R. From benzidine, salicylic and naphthionic acids. Colours. S. and J. 173. 5. Salmon Red. Sodium salt of diamido-diphenyl-urea-disazo-naphthionic acid. S. and J. 143. 6. Toluylene Orange R. From o-tolidine and m-toluylene-diaminesulphonic acid. S. and J. 197. 99 8. Cloth Orange. From benzidine, salicylic acid, and resorcinol. S. and J. 170. Quinoline Colours. Acid Colours. 41 Quinoline Yellow S. Sodium salt of quino-thalone-disulphonic acid. S. and J. 379. 3. Young Fustic (Cr.). 15. Anthracine (Cr.). Composition not published. 3. Old Fustic (Al.). Wood of Morus tinctoria. 6. Flavin (Al.). Quercetin prepared from Quercitron Bark. 2. Persian Berries (Sn.). 3. Young Fustic (Sn.). 4. Flavin (Sn.). 5. Quercitron Bark (Sn.). 6. Old Fustic (Sn.). 7. Tesu (Sn.). NOTES. The fugitive character of Narceïn as compared with Orange II., of which it is merely the sodium bisulphite compound, is very pronounced. The bright orange of Flavin with tin mordant changes rapidly during the first exposing period to an olive-yellow, which may be regarded as 'moderately fast.' A similar change is noticed in the case of Quercitron Bark and Old Fustic with the same mordant, the faded colour of the latter being, however, very dull. With aluminium and tin mordants Anthracine gives bright but very fugitive colours. CLASS III. MODERATELY FAST COLOURS. (WOOL.) The colours of this class show distinct fading at the end of the second period (July 1 to July 31, 1893), which becomes more pronounced at the end of the third period (July 31 to August 26, 1893). A pale tint remains at the end of the fourth period of exposure' (August 26, 1893, to February 19, 1894), and at the end of a year's exposure the colour has entirely faded, or, at most, mere traces of colour remain. Azo Colours. Wool Book III. Acid Colours. 2. Orange GT. From toluidine and B-naphthol-mono-sulphonic acid S. S. and J. 41. 4. *Mandarin GR. extra. From o-toluidine-mono-sulphonic acid and B-naphthol. S. and J. 78. 5. *Orange II. From p-sulphanilic acid and B-naphthol. S. and J. 73. 7. *Orange III. From m-nitraniline and B-naphthol-disulphonic acid R. S. and J. 33. 11. *Diphenylamine Orange. From p-sulphanilic acid and dimethyl From p-sulphanilic acid and diphenyl 12. Tropæolin Y. From p-sulphanilic acid and phenol. S. and J. 70. 15. *Metanil Yellow. From m-sulphanilic acid and diphenylamine. S. and J. 77. 16. Resorcinol Yellow. and J. 71. 18. From p-sulphanilic acid and resorcinol. S. Constitution not published. From p-toluidine-o-sulphonic acid and diphenylamine. S. and J. 79. 1894. R Wool Book III. Acid Colours. 28. *Curcumeïn. and J. 101. Nitro derivative of Diphenylamine Orange. S. 29. Azoflavin S. Same as Curcumeïn, but more highly nitrated. S. and J. 102. 44. * Bromine derivative of Metanil Yellow. Direct Cotton 2. Salmon Red. Constitution not published. 3. Congo Orange R. From tolidine, B-naphthylamine-disulphonic acid R and phenol (ethylated). S. and J. 202. 7. Congo Orange G. From benzidine, B-naphthylamine-disulphonic acid R and phenol (ethylated). 10. Toluylene Orange G. From tolidine, o-cresotinic acid, and m-toluylene-diamine-sulphonic acid. S. and J. 196. 23. Carbazol Yellow. From diamido - carbazol and salicylic acid. S. and J. 181. 24. *Cotton Yellow G. Sodium salt of diamido-diphenyl-urea-disazosalicylic acid. S. and J. 144. Mordant Colour. 24. Mordant Yellow (Cr.). Constitution not published. Mordant Colours. 5. Weld (Al.). Reseda luteola (whole plant). NOTES. The following colours become somewhat duller and apparently darker during the first and second periods of exposure :-Diphenylamine Orange, Metanil Yellow, Fast Yellow N, Azo-flavin S, Acid Yellow OO, and Aurotin. This appearance is only observed when the patterns are examined 'underhand,' i.e. by looking down into the fabric; when they are examined 'overhand,' i.e. by glancing along the surface, a normal fading of the colours is observed. This darkening is probably due to the presence of the diphenylamine group in the first four colours mentioned, and to the presence of the nitro group in the case of Aurotin, of which the alteration in hue reminds one of the change occurring in Picric Acid Yellow, though it is less pronounced. Mordant Yellow with aluminium and tin mordants gives colours which may well be classed with the fast colours. CLASS IV. FAST COLOURS. (WOOL.) The colours of this class show comparatively little fading during the first, second, and third periods. At the end of the fourth period of exposure' a pale shade remains, which at the end of the year's exposure still leaves a pale tint. Wool Book III. Nitro Colours. Ammonium salt of tetra-nitro-y-diphenol. Acid Colours. 3. *Palatine Orange. S. and J. 8. Hydrazone Colours. Acid Colours. 36. Tartrazin. Sodium salt of diphenyl-p-sulphonic-acid-osazone dioxytartaric acid. S. and J. 19. 39. Nitrazin Yellow. Sodium salt of dinitro-dixylyl-p-sulphonic acid-osazone-dioxytartaric acid. |