To distinguish how a book-plate
may have been produced.

A lithograph or a photo-lithograph may be distinguished from a woodcut, or from a copper engraving, by the following: By the quality of the lines, whether cut with the graver or etched upon copper; drawn with the pen or with the fine sable pencil. Each has a character of handling and manner of its own by which it may be recognised. A little observation of admitted examples with the aid of a strong magnifying glass will generally resolve this.

THE DIFFERENCE IN ENGRAVED OR
CUT LINES, AND ETCHED LINES.

Lines cut with the graver are invariably smooth and even, and have a clear silvery appearance; in isolated lines or cuts it will be observed that the beginning of the lines are finer where the graver has entered than where it stops. Etched lines, on the contrary, do not possess the same smooth-edged rigid character as those cut with the graver; and where greater strength of line is obtained it is by deeper etching with the acid bath, and in this the difference in the quality of line is more perceptible.

TO DISTINGUISH AN IMPRESSION
FROM PLATE.

In a plate engraving the lines are slightly in relief (and, if strongly engraved, or the paper thin, observable on the back). A sensitive finger will detect the stronger raised lines of the engraving. The mark of the plate, unless cut off, also betrays it; the engraved plate by Mr. Sherborn, facing page 27, will illustrate this.

TO DISTINGUISH A WOODCUT,
OR LINE PROCESS BLOCK.

In a block the lines of the design are indented slightly into the paper, which shows itself on the back of the print (unless thoroughly rolled out under heavy pressure). Close observation with the magnifying glass will show the edges of the lines to be slightly rough—by the ink from the face of the line being squeezed over the edge; in good printing this is not so apparent. A weakness with nearly all process blocks is that the edges of fine tints and outlying fine lines are apt to print heavier than they should, unless very carefully worked.

TO DISTINGUISH A LITHOGRAPH.

In a lithograph the surface of the paper is perfectly smooth, and not indented in any way. The examples of engraved plates printed from stone, and the litho. and photo-litho’s printed in brown ink, will serve to illustrate the qualities of lithography. Unless well printed, the fine lines are apt to show weak and rotten, or to have become thick and blurred, either in transferring to the stone or by too much ink on the printing roller.