Treatment of Old Rollers.
When rollers have been lying for weeks with a coating of ink dried on to the surface—a circumstance that often occurs, more especially when colored inks have been used—get an ordinary red paving brick (an old one with the edges worn away will be the best), place the roller on a board, then dip the brick in a trough of cold water, and work it gently to and fro on the surface from end to end, taking care to apply plenty of water, dipping the brick in repeatedly; and in a short time the ink will disappear. Nor is this all; for if a little care and patience is exercised, it will put a new face to the roller, making it almost equal to new; the coating of ink having, by keeping the air from the surface, tended to preserve the roller from perishing. Sponge off clean.
A Recipe for Printers’ Rollers.
Best white glue, one pound; concentrated glycerine, one pound. Soak the glue over night in just enough cold soft water to cover it. Put the softened glue in a fine cloth bag, gently press out excess of water, and melt the glue by heating it over a salt water bath. Then gradually stir in the glycerine and continue the heating, with occasional stirring, for several hours, or until as much of the water is expelled as possible. Cast in oiled brass molds, and give the composition plenty of time to cool and harden properly before removing from the mold and inking. See that the ink is well spread before bringing the roller in contact with type.
Temperature of the Press Room.
The temperature of the press or machine room ought to be as near as possible the same as that at which the ink is manufactured—viz., 16° of Reamur (68° Fahrenheit). If the temperature of the room, and consequently, of the iron receptacles the ink is kept in, be considerably less, the varnish of the ink will stiffen, the paper will adhere to the type and peel off, or, if this does not occur, there will at least be too little varnish in the ink remaining on the type, and too much carbon, which, of course, will not sufficiently adhere to the paper, and may be wiped off even when the paint is perfectly dry. But if the temperature of the work-room be too high, the varnish becomes too thin, the ink loses its power of covering well all parts of the types, which then look as if they had been printed with lamp-oil. Colors of different hues require generally a somewhat higher temperature than black, say 70° to 75° Fahrenheit, but any printer who wants to see a clear and sharp impression of his types on the paper should not neglect to look sometimes to the thermometer, too low or too high a temperature being much oftener the cause of unsatisfactory printing than the ink we use.
When to Wash Rollers.
The press or machine man must be guided by the condition of the face of the roller, and the eyes and fingers will be the best guides. Where machine rollers are required for a weekly newspaper, they should be washed ready for the first set of forms, and when the number is long, a second set should be got ready and inked to work the second side, as the paper throws off a quantity of cotton waste, and powder, and neutralizes the tack so necessary to the face of a good roller and a clear impression. Should a roller require cleaning for a hurried work, the old ink may be removed with turpentine, but must be done quickly, and immediately distributed on the ink table, or the face will harden.
Improved Dryer for Printing Ink.
A small quantity of perfectly dry acetate of lead or borate of manganese in impalpable powder will hasten the drying of the ink. It is essential that it be thoroughly incorporated with the ink by trituration in a mortar.