Scott #1254-1257 Color Variation

Posted this in a Facebook group. Neither plate block is tagged, all the words and numerals on the right plate block are uniformed on all 4 stamps, and are brown/slight golden brown. Anyone seen this verity before?

It also looks a lot more brown in person

Just an idea, but does it have an odor, like old smoke from cigarettes? Or maybe it is toned from light exposure, chemicals, or humidity/moisture from storage in glassine/paper?

No none of that. My thought was something like that, or faded/chemically altered at first. But the other colors, carimine and green, seem fairly in line color wise between the two blocks, and black would be the last to fade in between the three colors. Plus if it was something like cigarette, it wouldn't explain the uniformed color of all numbers and lettered of the right hand block.

It is likely it is color contamination (mixing of the red and green)

So would that make it a black omitted? Even if that was the case though, why would the black on the left block consist of black, carmine and green?

I suspect you have the same Giori press inking variance as shown in this thread on the 4 cent Whooping Crane issue:

https://goscf.com/t/61695

Not sure if that is the same, since the colors are still consistent on your link vs my blocks where the black itself is a different color.

I would have to agree with eyeonwall, that this was caused by ink contamination.

Although it is most likely just the red ink that mixed with the black. This can result in a brownish or maroon color.

See the pic below of the #702 "Red Cross" issue. Which in this case, the black ink contaminated the red ink of the cross, but the results would be similar.
I have seen the #702 error with various shades depending on the amount of contamination.

I should have said red mixed into the black as Mike said