Mexico : Official : Seek Id.

Would members please offer their opinion on this one?
Mexico Sc#O11 ?
2c looks like style A20 (Letter Carrier) which would suggest carmine.

Anyone seen a carmine colour changeling to bistre?
Comments welcomed.

Rod,
I can't help with the ID of the Mexico but I have a 10 l issue from Crete (SG 3, 1 Mar 1900), issued colour scarlet but is bistre. I suspect it has been tampered with. Sadly (and rather unhelpfully) I don't have a scan of it handy.

Some of the orange and scarlet early adhesives of Central and East Africa also oxidise from the issued colours of vermillion or scarlet to a reddish bistre when exposed to excessive heat and humidity, although this generally seems to affect mint rather than used stamps.

There is Sc 280a of the same style, an error in green. Not bistre of course but closer to bistre than carmine....... Sc 280a is the only issue in this style that is unwatermaked.

Thank you gentlemen, very helpful.
I'll check my watermark.

I have checked all my examples of colour changelings,
and indeed orange/red will sometimes go orange/yellow.
(But I don't hold much faith in stamps with inks of differing eras)

(scan incorrectly named yellow to red, should be red to yellow)

Gentlemen, I'll leave an "open finding"
I strongly suspect it to be a normal rosine colour changeling.

Wmk : No watermark evident
Perforation: Could be perf 12 but rough perfs support only a rough guestimate.
Postmarked 1897
Gibbons list no Official opt on the error green
The error green was produced apparently later in 1898

Gibbons evidence the OPT angled and inverted as my example

Cheers