French Morocco Unusual Color?

This first picture shows 2 copies of what I believe is Scott #91. The color is listed as brown violet. The stamp on the right appears to be the accurate color (matches a 3rd that I have). The one on the left is a bit off color, I guess less brown. I can live with it being a faded version of the real thing.



Now, for this pair, based on the design and denomination, they are both Scott #101 which is listed as violet. Clearly the stamp on the right is violet, but the one on the left seems to not be possible even if the violet were bleached out somehow. Could it simply be a fake/forgery/reprint that didn't use the same colors? Perhaps there is a more specialized catalog than my Scott Classic that lists different colors?

Maroon - some red = violet

Purple - red = blue

Reds and yellows fade first. Blues and black are most resistant to fading.

Yes, there are 2 shades for this stamp - listed by both Yvert and Maury - violet & violet-grey.

~Greg

SG France Part 6 5th Edition also lists two shades for each stamp:
2c claret and purple-brown
35c purple and greyish purple.
There is also a slight premium for the second-listed shade when used.

Thanks everyone for your replies.