[Joe_G.]

Not sure if this is the answer you are looking for, but the following is possible:

1) you can create a glass plate "positive" from an original glass plate negative, but not a negative directly from a negative.

2) you can create a negative from a print/photo positive by taking photo of it. This could be considered a second generation negative that could be produced at any point after the original.

OJ cabinets were made from original 1st gen negative where as N172s could be considered as creations from a 2nd generation negatives (once removed from the original negative; ie re-photographed images that have been doctored with advertising etc.).