Washing Forms.
Forms sent down to machine ought not to be wet too much with lye or with water, otherwise it becomes necessary to dry them before working, which takes time and often much trouble. The wet works up little by little to the face of the letter, and then the form becomes unworkable. It has often to be taken off the coffin, the feet of the types have to be thoroughly dried, then some sheets of unsized paper have to be placed under the form; it has also to be unlocked, shaken, locked up again, the sheets removed with the moisture they have imbibed, and then it is to be hoped the form will be workable. If not there is nothing to be done but to lift it and dry it by heat.
Lye is generally used for washing forms which do not contain wood blocks; turpentine where wood-cuts or wood-letters are to be found in them. The bristles of the lye-brush should be longer than those of the turpentine-brush, and, in order to preserve it, each brush should be properly washed with water after using, and shaken and stood up to dry. If this is not done the brush will last but a short time.
There is no good in taking up with the brush a large quantity of lye or turps, and to shed it at once. Yet this is too commonly done, regardless of waste. In order to wash a form well the brush should be passed lightly over all the pages, in order to wet them uniformly. Then they should be rubbed round and round, and finally lengthwise and crosswise. Leaning on the brush not only wears away the bristles, but sometimes injures the face of the type, too. It is a bad practice.
After washing, before printing, a sponge with pure water should be passed lightly over the form, and then the form should be dried with a cloth. Care should be taken not to use a woolen cloth, which is liable to leave little pieces on the face of the types, and to see that there are no hard substances in it. After printing it is always best to wash with turpentine. Lye induces oxidation of the types, while turps leave an oily film on them, which preserves them from the action of the atmosphere.
How to Prevent Off-setting.
A practical pressman says that a sheet of paper wet with glycerine and used as a tympan-sheet will prevent off-setting. This will be found better than using oiled sheets.
Printing Envelopes.
To prevent the lumpy particles of mucilage on gummed envelopes from “battering” the type, use a heavy piece of blotting paper as a tympan, and when beaten down, touch the injured part with a drop of water, which will bring up the impression again.