Most times the process of transferring or printing the image can be repeated numerous times, creating editions of the same image. Sometimes each individual print is retouched or added to afterwards, making it unique or one-of-a-kind. Other techniques involve using the same matrix but different combinations of inks and colors, also creating unique works.
Multiple "impressions" are made by printing new pieces of paper from the matrix in the same way. The total number of impressions an artist decides to make for any one image is called an edition. In modern times each impression in an edition is signed and numbered by the artist, but this is a relatively recent practice.
From the Latin word mater, meaning mother, the matrix is the form or surface on which the image to be printed is prepared, for example, a woodblock, a metal plate, a lithographic stone or a mesh screen.
This is the matrix, on a vinyl tile for "Stripe".
Formerly, when an artist was commissioned to execute a print, he was provided with lodging and living expenses, a printing studio and workmen, supplies and paper. The artist was given a portion of the edition (to sell) as payment for his work. Today, though artists get paid for their editions, the tradition of the "artist's proof" has persisted and a certain number of impressions are put aside for the artist to do with as he will. Artist's proofs are annotated as such or as A.P., or Épreuve d'Artiste or E.A.
A/P can also annotate a one off print, which can also be shown as 1/1 or U/S meaning Unique State
When all the prints are created from the matrix to be identical, this is called an ‘Edition’. The artist generally limits the edition to a certain number of their choice. He or she then indicates in pencil (usually in the bottom left hand corner) the number of each individual piece and the total number of copies in the edition, for example, 5/40.
I generally produce an edition of 15 which seems like a nice number!