Portugal 1953-1956 Scott #771 Color Mismatch

anyone have any ideas, I'm new to the Portugal stamps, and it seems one of two does not match up with the colors listed.

Quite common, in fact there are three shades.
Unable to locate any information that explains them.
Gibbons lists as "greenish black on pink paper"

Edwin,

My Afinsa Stamp Catalogue for Portugal (which I believe is the "Go-To" catalog for Portugal) lists the color as "Preto si salmão claro".

According to web translation, this is Black with Salmon or something like that. I think you have black salmon stamps there.

Scott's description of "gray black" doesn't fit - you're right. But I'm guessing they got it wrong.

By the way, the Afinsa number for this stamp is 773.