STEREOTYPE.
Stereotype, as we have mentioned in the former article, was introduced about the middle of last century; and as it is so intimately connected with the art of printing, we could not find a more appropriate place than immediately following that noble art.—Earl Stanhope has been named as the inventor; but for this we have not sufficient authority, and it appears extremely doubtful; as stereotyping appears to have been invented simultaneously, in various parts of England and Scotland, by different persons; still it was upwards of sixty years before it was brought to such perfection as to be applicable for any beneficial purpose.
When properly made known, it was hailed with approbation by those more immediately interested—the printers and publishers: but as experience more fully developed its powers, it was found available only for particular work. For the better understanding of this art, which is comparatively little known, we will give a description of the process, which we are enabled to do by the assistance of an experienced workman.
In setting the types, they are lifted from the case, one by one, with the right hand, and built in a small iron form, called a composing-stick, held in the left hand of the compositor, who sets line after line till the stick is filled, when he empties it upon a galley, and commences again in the same manner, till he has got as much up as will make a page; this page he ties firmly up, and places upon a smooth stone, or cast iron table. In this manner he continues, till he gets as many pages as will make a form, which consists of 4, 8, 12, or more pages, as the case may be. If this form is to be worked off at press without stereotyping, the pages are all imposed in one chass, and carried to press for working, and when the whole of the impression is off, it is thoroughly washed, and carried back to the compositor for distribution—that is, putting the types in their proper places. When these pages are to be stereotyped, they are imposed separately, and carried to the stereotype foundry, where they are examined, and all dirt taken from the face; they are then slightly oiled, and a moulding-frame put round each. The frame is filled with liquid plaster of Paris, which is well rubbed into the face of the type to expel the air. As soon as this plaster hardens, it is removed from the page, and shows a complete resemblance of the page from which it is taken. The mould is put into an oven to dry, where it remains till it resembles a piece of pottery; it is then put into an iron pan, in which there is a thin plate of the same metal, called the floating-plate; it has also an iron lid, which is firmly screwed down, and the whole is immersed in a pot of molten type-metal, which fills the pan by means of small holes in the corners of the lid. The length of time it remains in the pot depends upon the heat of the metal, but it is generally from ten to fifteen minutes, when it is taken out, and put aside to cool. On opening the pan, nothing is seen but a solid lump of metal, which, when carefully broke round the mould, a thin plate is obtained from the mass, exhibiting a perfect appearance of the page from which the mould was taken.—This is called a stereotype plate, which in general is not above the eighth of an inch thick, and is printed from in the same manner as a page of types. Such is the process of stereotyping, which has become pretty general throughout the trade, but is not much known to the public.