Alizarin Colours.
| Alizarin black | produces | light slate. |
| Alizarin orange | „ | bright orange. |
| Alizarin blue | „ | blue. |
| Azo-alizarin black | „ | brownish maroon. |
| Azo-alizarin brown | „ | reddish violet. |
| Alizarin red | „ | bright scarlet red. |
| Azo-alizarin blue | „ | slate blue. |
| Coerulein | „ | yellowish green. |
| Azo-alizarin yellow | „ | bright yellow. |
| Anthracene brown | „ | fawn brown. |
| Acid anthracene brown G | „ | brownish orange. |
| Acid anthracene brown R | „ | dull chocolate brown. |
| Anthracene blue | „ | pale blue. |
| Mordant yellow | „ | lemon yellow. |
Janus Colours.
| Janus yellow G. | produces | bright orange. |
| Janus yellow R. | „ | reddish orange. |
| Janus red | „ | dark maroon. |
| Janus claret red | „ | bluish maroon. |
| Janus brown R. | „ | dark reddish chocolate. |
| Janus blue B. | „ | bluish black. |
Natural Dyestuffs.
| Barwood | produces | salmon pink. |
| Logwood | „ | dull reddish brown. |
| Fustic | „ | bright yellow. |
| Turmeric | „ | yellow. |
| Brazil wood | „ | reddish brown. |
| Sapan wood | „ | light nut brown. |
| Sumach | „ | buff yellow. |
| Persian berries | „ | light orange yellow. |
| Madder | „ | red. |
| Quercitron bark | „ | light orange yellow. |
| Cutch | „ | fawn brown. |
| Campeche | „ | canary yellow. |
| Peach wood | „ | pale reddish tint. |
| Divi-Divi | „ | buff yellow. |
The leather is run in the dyestuff solution at a temperature of about 45° to 50° C. for about half an hour, and then lightly fat-liquored, if desired, and afterwards dried.
In addition to the dyestuffs mentioned above many basic colours may be employed after the treatment with titanium, some of these producing a colour lake with the titanium mordants.
As regards the permanency of the various colours to light, the reader is referred to an important paper by Mr. Lamb,[199] but in many cases the probable permanency is indicated by a number prefixed to the name of the colour in Roman figures, I. corresponding to the lowest, and X. to the highest permanency. In the research referred to, about 1500 samples of leathers dyed with coal-tar dyes were exposed to light for a series of “periods,” each equal in actinic power to nine days of the brightest summer sunshine. The most fugitive colours faded completely, even in the first “period,” and the most permanent before the end of the tenth. The prefixed numerals indicate to which of these “periods” the colour survived.
[199] Journal of Society of Chemical Industry, 1902, p. 156.