Czechoslovakia 1920-21 Doves On White Paper (10-H)

Anyone knows if the one on the right is actually on white paper? It's clear a difference in paper color but I can say for sure it's white paper.
Unfortunately I don't have any other stamp from this issue to compare.

As long as it is not coloured it is white :)

Sorry I don't think anybody here can answer your question,because a computer screen and a scanner are not sensitive enough to show the difference on its own . The difference on CZECH stamps to show the white paper ,cream papers and your yellow papers of some of the back of the book issues , would need a side by side scan and even that is questionable . a single stamp scan is worthless to say for sure

Yours look like yellow paper when compared to my white paper issues .

@floortrader
Please scan yours and post.
On my scan the one on the left is for sure yellow.

The center stamp is white paper ..

under UV light
no doubt that the right one is white
the scans and the eyes get mislead by the stamp color, which is brown for 10