There are many tricks - some of them, like tasting plaster are on a border of being superstitious. I taste paint for lime. Human sences are the mysteriose thing, tast is perhaps one of the most trasted, so you have to tast a thing to be sure that it is right - even if it does not make any sence.

Brush strocks in fresco are en essential part, in fact only fresco gives such thin strokes that of a single hair. This is due to the vehicle - water - the thinnest of them all. Even watercolour has gum-arabic as a binder - Fresco is a pure water.

Ilia