I wonder if your copied 8*10 negative will give the same quality Pt prints which you dad made (that is: if you want to make Pt prints which is not clear to me0. I assume the original negatives are lost. If you copy the Pt prints you also copy the paper fibers, the surface, this may or may not result in loss of sharpness perhaps. And if you plan on making Pt prints of these negatives, but sure they have enough contrast for that too. Not a easy road.

good luck,

best,

Cor