Error In Apollo Soyuz Link Up 1975 Stamp

Hello,

I have Apollo Soyuz link up 1975 stamp as shown below.
That stamp is missing some color starting with RED color. Any idea how this could happen?

The red end of the spectrum is the most prone to sun-fading. Your stamp shows the very typial effects of long-term light exposure and the red has faded away. Thus damage, not a color-missing error. Sorry.

This article provides additional insight and examples:
https://stampsmarter.org/learning/A...gelings.html

Thank you very much for your kind feedback! Appreciate it!

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Aren't also the green and yellow colors missing?

The term for this is changeling- https://stampsmarter.org/learning/A...gelings.html

Yes, even the blue is a washed out pale blue, not the deep dark blue of the original. And the black at the far left end of the capsule is a grayish, not a dark black. A true missing color issue would have all other colors looking fairly normal, and just the one (or more) completely missing.

I vote sun fade rather than a chemical changeling. A popular stamp like this one, with the great cancel, could have been pinned up on someone's bulletin board, or hanging on the wall in a picture frame, for countless decades.

I'm really curious since I have a mint never used stamp of this issue.


1570f is a known Scott specialty of this stamp missing yellow. There are 3 tones of blue, which only 1 is apparent. Also red, yellow, and black. Almost seems like it got grey and light blue only.

On my sample, I've looked under with magnification and not seeing any red or even outline of it. IDK...

I'm taken another stamp and labeled date exposing to the direct sun to see if shifts like this or differently.

If one enlarges the original image, then the ghost of the red is still there.