|
Hi Allan,
As far as I'm concerned he used bistre and sepia mixed up. I read once that it looses its quality over time. Rembrandt made lots of experiments and he always mixed pigments. But if you say it is pure bistre, I'll believe you.
I've seen some very old stuff in bistre including maps and portraits, it's like Van Gogh's work which has lost some of its colors, but is beautiful.
Now I cannot recall whether the material I read about it was talking about its permanency on paper, fabric or whatever.
I'm sorry if I made a big mistake here.
And Beth, you should look for restorer's suppliers. Artists suppliers are usually concerned about the latest materials.
|