An artist's proof btw is a print made by the artist, typically before any limited edition production is authorized and offered for sale, to insure the color and quality of the print meets the artist's standards and approval. As such some artist proofs, are slightly different as they become the print that guides the artist in making any final adjustments to the source photographs or printing calibrations for the full edition. The differences may be so subtle that only the artists eye would discern any variation, but because of those possible variations from the authorized edition, each artist's proof is a unique, one of a kind print unlike any other distinquished in one specific way. Often Dan's artist's proofs, for example are printed slightly larger or with greater margins than the official limited edition set to test the print quality when pushed beyond the photograph's normal resolution through enlargement or to verify the printed area is truly square in all corners. The proofs made by the artist are the final check to insure the authorized edition meets the artist's standards so any particular artist proof may be slightly different than the following edition prints which will have had any undesired color shifts or other 'imperfections' corrected.