Unusual Color Question

I know a lot of stamps range in colors such as reds but this is a lot different. I cannot find anything about it on the web. See the pic side by side of the 2 cent stamps.
Let me know what you think.

Thank you

It is just a very faded version probably exposed too long to sunlight.

Good answer but wouldn't it be a more faded red?

I was thinking it might be caused by being exposed to the elements, I had the same question about these.

I think that the left one is slightly faded from exposure to light and that the right one is slightly oxidized (or as chemists would say - reduced) giving it a darker than normal appearance.

Mermaid 21:
As to the 1¢ stamps, the one at the bottom of the scan may be an offset issue (Scott 525) and the one at the top of the scan a normal flat plate printing.

I'm not sure either one is a changeling. The first is likely the Scott-listed scarlet & black. The second likely the Scott-listed dark carmine and black.

...the second stamp slightly darkened by exposure to the elements (I think you can see hints of the "natural" dark carmine color at the sides near the stomach of the female figure, and also at bottom, around the word "CENTS.")

As I've (and others have) pointed out numerous times in other threads, it's always hard to judge shades from photographs where color & exposure are not well-controlled. It's typically nothing more than a guess.

It's possible that a careful application of hydrogen peroxide to the front of the second stamp would reverse some (or all) of the darkening/suffuretting.