Following my post from this past week on the so-called varnish square on the green dollar commerce stamps, Dave Thompson sent in a scan of the $2 dollar stamp below. The stamp has the surcharged numeral of R191, but the stamp is not green. The color is more like that of R185, the $2 gray. The varnish square,or the lack of it, is not the issue here. The big question here is one of color. How did this stamp get this way? I might have dismissed Dave's stamp as a one-off chemically induced changeling, with little philatelic significance. But then I recalled that I might have a similar stamp in my own collection.
Dave Thompson's R191
My stamp clearly had the varnish spot. It appears Dave's did not. But why are these stamps this color? I never gave too much thought to the stamp above; it has been in my collection for years. But now that there are two, this is a bigger deal begging for an answer.