All sorts of oddities pop up when it comes to Topps proofs. There are rare proofs that are valuable, such as the 1977 Reggie Jackson-Orioles variation or 1967 Roger Maris-Yankees team version but many of them do not curry favor with collectors. Another type of proof is the color progression proof, where Topps would print a subject in each discrete color in the proof stage and then sometimes combine two or more colors as they neared final printing. One good example of this is this 1962 Baseball Stamp grouping:
I'm not sure where that came from-I've had this scan for ten years and cannot recall. That looks like a green/yellow progression. There should be six colors in all I believe, for products of this era. One piece I do have provenance for (because it's mine), is this 1967 San Francisco Giants Baseball Disc of Herman Franks:
It too is missing some color but has the black process, unlike the stamp proofs. The Giants Discs were a distinct issue from the other 1967 Baseball Discs, which depicted Major League All Stars. Both Disc sets were only issued in proof form and the thinking is they were going to be turned into pins. I think a post on them is overdue and will have something in short order.
Happy New Year folks! 2013 will be a banner year around here, so stay tuned,