For Modern Prints and Photographs:  The standards employed by auction houses vary widely, from those that do not mention margins at all to those terms such as "Full Margins", "Wide Margins", "Small Margins", "Trimmed Margins", "Without Margins", or, the ambiguous and non-committal "Margins".  The reader must conclude for himself what the relative difference is between these terms. 


In modern times, the term "Full Margins" may be used for a work that is printed to the edges of the sheet and therefore has no margins, to a work that has huge or small margins whose margins are in the same condition as was the entire edition when it was originally printed.


For Old Master Prints, the standards are more defined as follows: 


Platemark:  This indicates that the margins have been trimmed to the platemark that appears on an intaglio print. 


Thread Margins:  Indicates that the margins of an intaglio print have been trimmed away to somewhere between the inner and outer sides of the "filet" that exists between the outer side of the image and the outer side of the platemark. 


Trimmed: This term is given if the margins have been trimmed, but not so drastically as to qualify for the thread margin category.  The extent of trimming may be only fractional, and in some cases may be trimmed only on one side. The degree of trimming may sometimes be assessed by referring to the auction catalogues. 


Without Margins:  This means that the margins have been cut off all the way around to or on the borderline, or just outside the image. 


Trimmed into the Image:  One or more sides of the image of the work has been cut away. 


Remargined: Items that have new margins grafted on have been remargined.  The original sheet may be trimmed to the platemark or within it.  The term appears if even one of the margins is not original. 


Many true connoisseurs feel the quality of the impression of the item and its overall condition are far more important than the margins.  For a typical example of this, see the works of J.A.M. Whistler, who himself cut away the margins on some of his prints.  


In fact, as a conclusion to this dissertation on margins, please consider Whistler's "Propositions", published with "A Set of Twenty-Six Etchings" in 1886: 


"IX.  That the habit of margin, again, dates from the outsider, and continues with the collector in his unreasoning connoisseurship - taking curious pleasure in the quantity of paper.

X.  That the picture ending where the frame begins, and, in the case of the etching, the white mount, being inevitably, because of its colour, the frame, the picture thus extends itself irrelevantly through the margin to the mount.

XI.  That wit of this kind should leave six inches of raw canvas between the painting and its gold frame, to delight the purchaser with the quality of the cloth."