Topps does use CMYK, although there are some years where it really looks like there are some other colors as well. Usually in the solid areas like team banners etc.
In theory, yes the progressive proofs should be the identical layers to the issued cards. For the 70's and before that's more likely. From the mid 80's on, I believe they used multiple printing plants, possibly producing different products. So maybe Rack packs from one, wax from another.
Any problems found at that stage in proofing that got corrected may show up as two different progressive proofs.
Even if the plants are the same, there can be small differences between runs, or between cards on different parts of a sheet. That's more likely in the era before 132 card series. And also possible for 132 card series before 1974-5 when they combined all the series.
I know for sure that 88 Score were screened differently for different press runs. In other words, every card from the set comes with at least two different versions most of which can only be told apart with a magnifier. (And three different sorts of cutting, I haven't checked for differences within each sort of cutting, but the most common comes two ways for sure.)
Steve B
|