Hi Anneke,
I have never tryed the JoSonja paints, but I was a member of a German dollforum for a time.
The ladies on there used those paints and found out that they do fade in time.
Especially the color red fades the most.
Most of the ladies on the German forum switched to the real paint from Nikky creations.
And now puppentraumland sells airdry paints too, I don't know if they are any good.
That is all I know about those paints, maybe someone on her has used the paints and knows more.

Geja.