Some of these reactions can be applied to the printing processes with the
bichromates, etc. The paper should be coated with galatine. See the
Appendix.
Other colorations can be obtained with dyes in utilizing (as shown by
Persoz) chromous chromic oxide as a mordant: alizarine, Brazil and yellow
wood (morus tinctoria), Fustet (rhus cotinus), etc. The extent of this
work does not admit of describing the numerous processes which can be
employed; they will suggest themselves to the chemist.
The alkalies employed with the dyes should be employed in diluted
solutions, as being liable to produce reticulation. By applying the
coloring matters and the mordants thickened with a little starch, the
image can be colored with different colors. Lantern slides can be thus
colored with great ease.