I can't handle colors and especially their names in different languages.
As a collector of German stamps, the Michel Color Guide is essential in identifying colors.
There are shades that are still difficult for me to identify.
For the 12 pf stamp the recent color name is schwarzlichrosarot / dunkelsiena and corresponds perfectly with the one in the color catalog.
PostmasterGS- Thank you for the information about of "identical colours"
I took 2 pictures with the lens of my minimicroscope.
Due to the LED light, the color changes but I only watched the similarity of the 2 colors.
In the picture on the bottom left, the colors appear different but I can confirm that it is the same color (I think so).
The resemblance is better seen in the picture on the top left where the horizontal lines are approximately the same thickness as the vertical ones.
Another stamp from my collection of mysterious stamps ("a" or "b" colour?)