Regarding your question about artist materials...

Expressions researched:
"Regarding your question about artist materials"

1969 Correspondence

You may use any materials which will be useful in producing nice paintings.

Letter to Indira -- Los Angeles 25 February, 1969:

For the Krishna book we will require paintings, so we will not need any etching and woodcut. So you can send me some samples of your paintings and then I'll give you some suggestions. But anyway, you continue to improve your very good artistic talents and it will soon come to the perfectional stage. Regarding your question about artist materials, you may use any materials which will be useful in producing nice paintings.