Thank you very much.
But smelling on my Testors enamel colours after having read your reply, I doubted a bit.
And I was right.
Here is a good explanation ( I know, I could have read it before I asked here, but I did it only now. Well... )
https://en.m.wikipedia.org/wiki/Enamel_paintEven on the picture you see "oil based enamel".
I doubted because in my Testors "enamels" I definitely smell things that are not the typical ( color ) oil smell but solvents, just as being used elsewhere as well.
Regards,
Roland