Library of Congress usually has different versions of digitized works. see this example
What is "color film copy transparency"? and what is its different with "digital file from original"?
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For color film copy transparency, they took a color photograph (negative), developed a color transparency (positive) and scanned the transparency to produce a digital file. Digital file from original means that the original was either scanned or digitally photographed. It has to do with what was digitized, was it the original or some kind of copy.