They should be damped, and evenly trimmed and pasted all over with thin best glue or starch, and well rubbed down with a piece of clean paper over the print. If any of the glue or starch oozes out from the sides, it should be wiped off with a clean damp sponge. As photographs lose their gloss in mounting, they must be rolled afterwards in order to restore it. A special machine is used for this.
But it may be wished to introduce the silver print without mounting on a board. To do so, and to keep the print straight, paste a very thin paper on the back, stretching the paper well; this will counteract the pulling power albumen has, and the print will, if this be done properly, remain perfectly straight and not curl up.
Albumen.—Desiccated egg-albumen is now well known in the market in the form of powder. Three teaspoonfuls of cold water added to every 1 ⁄ 2 teaspoonful of powder represents the normal consistency of egg-albumen.[13]
[13] See Chapter on Finishing—“Albumen.”
The manufacture of egg-albumen in the neighbourhood of Moscow is carried on in the houses of the country people. The albumen however is generally roughly prepared and of bad appearance, and often spoils. But egg-albumen is also produced on a manufacturing scale in the neighbourhood of Korotscha, the largest establishment there numbering sixty to seventy workwomen, using about eight million eggs yearly, other establishments using less in proportion.
Albumen is also largely manufactured from blood; 5 oxen or 20 sheep or 34 calves are said to yield the same quantity of dry albumen, viz., 2 lbs. In producing blood-albumen for commerce, the objects borne in mind are the attainment of a substance whose solution is free from colour, possesses coagulation, and which is cheap.
To prevent tools, machines, etc., from rusting.—Boiled linseed oil, if allowed to dry on polished tools, will keep them |172| from rusting; the oil forms a coat over them which excludes contact from air.
Dissolve 1 ⁄ 2 oz. of camphor in 1 lb. of lard; take off the scum, and mix as much blacklead as will give the mixture an iron colour. All kinds of machinery, iron or steel, if rubbed over with this mixture, and left on for 24 hours, and then rubbed with a linen cloth, will keep clean for months.
To clean silver mountings.—To restore the colour of tarnished silver clasps, etc., boil the goods, either silver or plated, in enough water to cover them. For every pint of water put into it 2 ounces of carbonate of potash and a 1 ⁄ 4 lb. of whiting. After boiling them for about a quarter of an hour, clean with a leather, brush, and whiting. They will then look as good as new.
To clean sponges.—Soak the sponge well in diluted muriatic acid for twelve hours. Wash well, then immerse in a solution of hyposulphate of soda to which a few drops of muriatic acid has been added a few moments before. When sufficiently bleached, wash well, and dry in a current of air.