When a print is numbered, the numbering is usually handwritten below the image as a fraction. The top number is that of the particular impression, and the bottom number is the size of the edition. Since there may be artist's proof prints in addition to the total edition, the denominator may be slightly below the number of impressions in the complete run. The print number is for cataloguing identification only and does not indicate the order of printing. No individual prints were numbered before the beginning of the twentieth century.
A numbered print is designed to show the limit or size of a print edition. The number is generally placed over the size of the edition. For example 12/500, indicates that the print is number twelve out of an edition of 500. Lower numbers used to mean a sharper image, but with modern printing, the last print should be as sharp as the first "off the press".
Each copy of a limited edition print is marked with two numbers separated by a slash mark. The first number identifies the particular copy, and the second indicates edition size: 42/950, for instance, identifies print number 42 of a 950-copy edition. (See Artist Proof and Lithography)