Boil twice for one minute with dilute ammonia (1:100) and small piece of white cotton. Keep the ammoniacal extract. X. Much color is stripped but cotton remains white-Acid dyestuff. Boil with hydrosulphite A. Decolorized. Color is not restored either by air or by persulphate. Azo Group No. 11-Acid Azo Blue, e.g., Lanacyl Blue. Not decolorized, but color changed to bluish red. Decolorized and color restored on exposure to air. Ammoniacal extract is colorless. Fe in ash. No. Ammoniacal extract is blue and on adding NaOH at once becomes yellow. No. 5 Indigo extract. Ammoniacal extract is blue and on adding NaOH becomes violet on heating. No. 6 Thiocarmine. Decolorized. Color does not return on exposure to air but is restored by persulphate. Triphenylmethane Group. Ammoniacal extract is colorless but becomes blue Y. Little or no color is stripped. Cotton remains white or is tinted. Boil with 5 per cent. sodium acetate and white cotton for two or three minutes. Cotton is stained--Salt dyestuff. On reduction with hydrosulphite A the color is not restored either by air or persulphate. Azo Group No. 3-Diamine or Benzo Blues, &c. Cotton remains white. Boil with a little aniline oil. Blue solution which on evaporation to dryness Solution is light brown or colorless-Mordant dye- stuff. dants. Boil with hydrosulphite A. Color of wool unaltered. No. 15 Alizarine, Cyanine, or Anthracene Blue. Color changed to dark brown, becoming blue again Decolorized, but color returns on exposure to air- Treat fibre with conc. H2804. Green Solution No. 17-Brilliant Alizarine Blue. EXAMINATION OF GREEN SHADES. TABLE V. Green shades are frequently dyed with mixtures of yellow and blue dyestuffs. The following single dyestuffs also come into consideration: 1. A basic safranine-azo color, such as Janus Green or Diazine Green. 2. A basic azine, thiazine or oxazine, such as Fast Green M, Azine Green, Capri Green, Methylene Green, &c. 3. A basic triphenylmethane dyestuff, such as Malachite Green, Methyl Green, Brilliant or Ethyl Green, Solid Green, Setoglaucine, &c. 4. An acid azine, oxazine or thiazine, such as Azine Green S. 5. An acid triphenylmethane dyestuff, such as Acid Green, Light Green, Guinea Green, Wool Green, Neptune Green, Naphthalene Green, &c. 6. An acid azo color, e.g., a mixture of an Azo Blue and Azo Yellow. 7. A salt dyestuff, such as Diamine Green, Columbia Green, Chloramine Green, Benzo Green, &c. 8. Coerulein, Alizarine Green S. 9. Alizarine Cyanine Greens, Alizarine Viridine. 10. Alizarine Green G, or B (oxazine group). 11. Nitroso mordant dyestuffs, e.g., Gambine Y, R, and B, Dioxine, Dark Green and Naphthol Green. 12. Azo mordant dyestuffs, such as Diamond Green and Chrome Patent Green. A. ANALYSIS. Boil twice for one minute with 5 per cent. acetic acid. Color is stripped-Basic dyestuff. Boil with hydrosulphite A. X. Decolorized. Dark violet returns on exposure to air. Decolorized. Original color returns on exposure to air. Azine, Oxazine or Thiazine Group-No. 2 Fast Green M, Azine Green, Capri Green, &c. Decolorized. Color does not return to exposure to air but is restored by persulphate. Triphenylmethane Group No. 3-Malachite Green, Brilliant Green, Setaglaucine, &c. B. Color is stripped-Acid, Salt or Mordant dyestuff. X. Boil twice for one minute with dilute ammonia Boil with hydrosulphite A. Decolorized. Color returns on exposure to air. Decolorized. Color does not return on exposure to Decolorized. Color is not restored either by air or persulphate. Azo Group No. 6-chiefly mixtures of an Azo Blue and Yellow. Y. Little or no color is stripped. Cotton remains white or is stained. Boil with 5 per cent. sodium acetate and a piece of Cotton is deeply stained-Salt dyestuff. No. 7 Cotton remains white-Mordant dyestuff. Color changes to brown-Alizarine Group. Original color returns on exposure to air. No. 8 Original color does not return on exposure to air Decolorized or changed to light buff. Color returns on exposure to air-Oxazine or Thiazine Group No. 10-Alizarine Green G or B. Color does not return on exposure to air or upon oxidation with persulphate. Nitroso or Azo Group. Boil with conc. hydrochloric acid. Fibre and solution light brown-Nitroso Group Fibre blue and solution colorless. Azo Group EXAMINATION OF BROWN SHADES. TABLE VI. Brown shades are usually dyed with mixtures of dyestuffs such as reds, oranges, blues, and greens. Even the brown dyestuffs issued by the color manufacturers are to a large extent mixtures. The following scheme is applicable to single dyestuffs or to mixtures composed of two or more dyestuffs of the same group. If dyestuffs of different groups are present (i.e., an azo orange with a blue of the triphenylmethane series), the respective tables must be consulted. The following single dyestuffs come into consid eration: 1. Basic Browns, such as Bismarck Browns or Vesuvine. 2. Acid azo colors, such as Acid Brown R, Fast Brown O, Resorcin Brown, Naphthylamine Brown, &c. 3. Salt dyestuffs of the azo group, such as Diamine Browns, Columbia Browns, Toluylene Browns, Dianil Browns, Benzo Browns, Congo Browns, Hessian Browns, Sulphon Browns, &c. 4. Salt dyestuffs of the stilbene group, e.g., Mikado Browns. 5. Anthragallol (Anthracene Brown). 6. Cutch. 7. Chromogen. 8. Mordant azo colors, such as Anthracene Acid Browns, Acid Anthracene Browns, Acid Anthracene Brown, Palatine Chrome Brown, Acid Chrome Brown, Diamond Brown, Metachrome Brown, &c. Also, Maganese Brown. |