The change of Madder Red to Orange.

Practical Magazine 17, 1876

(Chemistry applied to the Arts, Manufactures, &c.
Dyeing, Calico Printing, Bleaching, Tanning, and Allied Subjects.)

— M. C. STROBEL, while studying the action of nitrous vapours on various printed colours, found that they destroyed most aniline colours and indigo blue, but brightened vapour greens and blues. He then applied them to madder red, and obtained a beautiful orange, which does not turn to red under the action of boiling soap-baths.

The experiment answered as well with vapour reds as with those obtained by dyeing on textures, whether oiled or not. His mode of operation is this. Into a wooden case containing the coloured texture he introduces the nitrous vapours obtained by the action of nitric acid on starch. The gas is previously cooled by passing through a flask surrounded with water. An exposure of four or five minutes is necessary to effect the change of the red. If the operation is interrupted before that time, the orange obtained will turn to brown under the action of soap and alkalies.

M. Strobel’s observation is new, and its importance will be appreciated by all who are engaged in dyeing textures. If the process above described cannot be employed in industry now, the time may be anticipated when the substance which produces this beautiful orange can be prepared directly, and applied to textures. We shall then have another fast colour which will not fail to be extensively used.

- Bulletin de la Société Industrielle de Mulhouse

.