Eugene Smith made copy negatives of some of his most important images and made his later prints from these copy negatives. The results are a slight loss of printing scale (more contrast and less gradations) and detail, but if you didn’t have the prints side by side you would have a very difficult time telling one from the other.
Why did Smith do it? Apparently with "Walk to Paradise" he had simply lost the negative. When CBS Sunday Morning worked on a Smith special, they asked if they could borrow the negative to make some prints. Smith had to break the news that he did not have it. CBS asked if they could borrow his vintage print to make a copy negative. When Smith saw the results, he asked CBS for the negative, with which he then produced virtually all the prints of Walk to Paradise currently in the market. Obviously, the vintage (and we will discuss that factor later) print exhibits qualities that the later prints do not and is much more highly valued.
Smith went on to make his own copy negatives, which he used on particularly troublesome prints, like his famous Minamata image. Prints made from the original negative are about 40-50% higher than prints made from the copy negative.
Source was http://www.iphotocentral.com/collect...ew.php/11/11/1