USSR 1968 Most Interesting!

Now this is a most interesting Soviet stamp. Issued in 1968, I recently found that I have a version with what looks to me like two missing colours.

This is the normal stamp:



But what I find interesting is that the scan of the error stamp shows a significant amount of yellow and a smaller amount of pale green:



Yet, to the naked eye, this stamp is simply black and violet-grey. The yellow cannot be seen at all, even when the stamp is being looked at closely with a magnifying glass, while the pale green looks more like bone-white.

Does anyone know what's going on here?

My first impression is color changeling due to sun or chemical exposure.

Surely, something like that could be said about any stamp with missing colours.

If you're correct, do you think it explains why the yellow cannot be seen by the naked eye but can be seen when illuminated during the scanning process?

That and color adjusting software in a scanner. Perhaps if you take the stamp out into the bright light, as in outside in the sun you too will see yellow. That said, yellow was not the only affected color.

I will do that (when we get some bright sun). Thanks for the suggestion.

Personally, I doubt that it's a colour changeling. Neither the black nor the the violet-grey have changed at all. It would have to be a very selective form of damage to have left these two colours intact. I would add that colour changelings usually look like they have taken some punishment. The changes in colours are also uneven and easy to spot.

All color do not react the same to the various processes which lead to a color changeling.

Both stamps are used and over 50 years old. There is no way to tell what environmental process has happened, but it looks very much like a changeling


Peter