On Mon, 14 Jul 2003 16:19:15 +0100, Andy Dingley
wrote:


But if you buy the cheapest set of paints from a local craft shop,
then you've no idea what you're getting. Many of them now contain
synthetic dyes of uncertain (or even well known) instability. This is
a serious issue with some artists and archival-grade conservators.

What about universal colorants? Is there any way to verify the
quality of the ingredients?

Thanks,
Barry