This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
See also Chromos, Copying Processes, and Transfer Processes.
The decalcomania process of transferring pictures requires that the print (usually in colors) be made on a specially prepared paper. Prints made on decalcomania paper may be transferred in the reverse to china ware, wood, celluloid, metal, or any hard smooth surface, and being varnished after transfer (or burnt in, in the case of pottery) acquire a fair degree of permanence. The original print is destroyed by the transfer.
A biscuit-baked object is first coated with a mixture of alcohol, shellac, varnish, and liquid glue. Then the prepared picture print is transferred on to this adhesive layer in the customary manner. The glaze, however, does not adhere to this coating and would, therefore, not cover the picture when fused on. To attain this, the layer bearing the transfer picture, as well as the latter, are simultaneously coated with a dextrin solution of about 10 per cent. When this dextrin coating is dry, the picture is glazed.
The mixing proportions of the two solutions employed, as well as of the adhesive and the dextrin solutions, vary somewhat according to the physical conditions of the porcelain, its porosity, etc. The following may serve for an example: Dissolve 5 parts of shellac or equivalent gum in 25 parts of spirit and emulsify this liquid with 20 parts of varnish and 8 parts of liquid glue. After drying, the glaze is put on and the ware thus prepared is placed in the grate fire.
The process described is especially adapted for film pictures, i. e., for such as bear the picture on a cohering layer, usually consisting of collodion. It cannot be employed outright for gum pictures, i. e., for such pictures as are composed of different pressed surfaces, consisting mainly of gum or similar material. If this process is to be adapted to these pictures as well, the ware, which has been given the biscuit baking, is first provided with a crude glaze coating, whereupon the details of the process are carried out as described above with the exception that there is another glaze coating between the adhesive coat and the biscuit-baked ware. In this case the article is also immediately placed in the grate fire. It is immaterial which of the two kinds of metachromatypes (transfer pictures) is used, in every case the baking in the muffle, etc., is dropped. The transfer pictures may also be produced in all colors for the grate fire.
Smooth unsized paper, not too thick, is coated with the following solutions:
Gelatin, 10 parts, dissolved in 300 parts warm water. This solution is applied with a sponge. The paper should be dried flat.
Starch, 50 parts; gum tragacanth, dissolved in 600 parts of water. (The gum tragacanth is soaked in 300 parts of water; in the other 300 parts the starch is boiled to a paste; the two are then poured together and boiled.) The dried paper is brushed with this paste uniformly, a fairly thick coat being applied. The paper is then allowed to dry again.
One part blood albumen is soaked in 3 parts water for 24 hours. A small quantity of sal ammoniac is added.
The paper, after having been coated with these three solutions and dried, is run through the printing press, the pictures, however, being printed reversed so that it may appear in its true position when transferred. Any colored inks may be used.
A transfer paper, known as "décalque rapide," invented by J. B. Dur-amy, consists of a paper of the kind generally used for making pottery transfers, but coated with a mixture of gum and arrowroot solutions in the proportion of 2.5 parts of the latter to 100 of the former. The coating is applied in the ordinary manner, but the paper is only semi-glazed. Furthermore, to decorate pottery ware by means of this new transfer paper, there is no need to immerse the ware in a bath in order to get the paper to draw off, as it will come away when moistened with a damp sponge, after having been in position for less than 5 minutes, whereas the ordinary papers require a much longer time.