Gary, pearl paint sells/sold "fresco paint" which was just a variation of universal tints. when I talked to them and asked if it is intended to be used in buon fresco they did not have a clear ansver and told me that that was just a brand name.

as you know a bucket of lime wash cost $3 to make but I can give you a list of companies thet sell it from $75 and up per bucket.

and Keim paints or others alike can not be used for buon fresco painting. But for painting over dry plaster they are possibly the best.

Gary did you try to keep the keim painted wall wet for a long time? I've met a keim distributor, very nice lady she said that if the wall will be soaked for a long time it will dissolve the paint (not that buon fresco will resist such treatment) She gave a lecture at the mural conservation symposium at Getty (i went there to give them some s** about total absence of any kind of support for fresco recearch and preservation)