Page:The Art of Bookbinding, Zaehnsdorf, 1890.djvu/210

170 cold water, and then gently boiling it, a beautifully white and strong paste is made. It dries almost transparent, and is a most useful paste for fine or delicate work.

Paste.—For ordinary purposes paste consists simply of flour made into a thin cream with water and boiled. It then forms a stiffish mass, which may be diluted with water so as to bring it to any required condition. It is sometimes of advantage to add a little common glue to the paste. Where paste is kept for a long time, various ingredients may be added to prevent souring and moulding. A few cloves form perhaps the best preservative for small quantities; on the larger scale carbolic acid may be used; salicylic acid is also a good preservative, a few grains added to the freshly prepared paste will entirely prevent souring and moulding. Paste is now made on a commercial scale by various Paste Cos., who send it out to all parts. The paste is exceedingly good, and keeps a long time. Photographs.—A few words respecting the treatment of photographs may not be out of place here.

To remove a photograph from an old or dirty mount, the surplus of the mount should be cut away; it should then be put into a plate of cold water and be allowed to float off, A little warm water will assist in its coming away more easily, but should it not do so, the photograph has probably been mounted with a solution of india-rubber, and in that case, by holding it near the fire, the rubber will soften, and the print may easily be peeled off. Very hot water is likely to set up a reaction if the prints were not well washed by the photographer when first sent out.

In mounting photographs, white boards should, as a rule, be avoided, because the colour of the boards is more pure than the lights of the photograph, and deaden the effect. A toned or tinted board is more suitable.