(1175) Chromo-Lithography.

Manufacturer and builder 2, 1875

Q
I am seeking information on the subject of chromo-lithography. If you will answer the following questions, you wil1 greatly oblige the subscriber:
1. How is the paper on which chromos are printed, prepared so as to prevent the oil in the colors from striking through and soiling the sheet?
2. What difference, if any, is there between paper intended for chromos and that used for ordinary lithographs or steel engravings?
3. After the chromo is printed and strained on muslin, is it necessary to size it before varnishing? or is it to varnish the picture over the color without any preparation?
4. What kind of varnish is best for chromos?
5. Is Canada balsam, when used as a varnish for chromos, likely or liable to crack?
6. When straining a chromo on muslin, do you paste the paper and let it soak?
7. In case of pasting the paper, does it not expand with the dampness, and thereby tend to crack the oil color?
8. What is the best kind of paste to use?
- O. W. M., Woodbridge, N. J.

A
There is no oil in the color, but it is prepared with an equivalent substance which poaseenes the valuable property of not striking, through paper. Notwithstanding we have found out what this substance is, we do not feel at liberty, out of consideration for the manufacturers, to publish its name.
2. The whole difference to that the paper for chromos is prepared with an extra sizing.
3. It is not necessary to size the chromo before varnishing, being equivalent to an oil painting, any clear varnish may he put on at once.
4. Mastic varnish, the same as used for oil painting, is the best, but copal, damar, or any other clear varnish will do.
5. Canada balsam will not crack more than other varnishes, but it dries too slowly.
6. Put the paste on the paper and let it soak a few minutes, then put on the canvas or cardboard, and it will stretch smooth in drying.
7. The paper expands a little with the dampness, but the color in elastic enough to expand also, and cracks are not to be feared.
8. Any paste will do, such as boiled wheat flour.