The powder gold was, however, generally used only for painting in fine gold lines and heightening miniatures, although in the latter part of the fifteenth century matt gold grounds were often used as borders round miniatures, etc.
The raised gilding was, however, used more often, and the various recipes given in the different MSS. are generally very similar to those given by Cennino. Sometimes chalk or pipe-clay is used instead of gesso, and occasionally parchment size or fish-glue is recommended as a medium for mixing it with.
Endeavouring to work from these recipes is no easy matter, and the student is not advised to waste too much time in experimenting in this direction. Although there is a certain amount of fascination in trying the various preparations and methods, there is so much that is important that should claim the attention of the student that it is hardly profitable for him to spend a lot of time trying to work from these old formulas when it might be better employed.
One cannot help being interested, however, in these old recipes and directions for applying gold to vellum.
CHAPTER XVII
THE USE OF GOLD
Gilding, in illuminated work, is done with either gold-leaf or shell gold. Gold-leaf is the metal that has been beaten out into thin sheets, and shell gold the same ground up and mixed with gum and honey. Shell gold is so called on account of the fact that it is sold in small shells ready for use.
The student is especially warned against using any of the varieties of gold paint for work that is desired to be permanent. These are mixed up with powdered bronze, and, in course of time, will turn black.
Shell gold is painted on in the same way that other colours are. A small brush should be used, so as not to waste any more than is absolutely necessary. It is also essential that quite clean water should be used, to ensure the gold being as bright as possible, as if the water is contaminated with colour it will dull the gold when mixed with it. The great disadvantages of shell gold are lack of brilliance and also the expense. It is, however, very useful for putting in very fine lines, which are difficult when using gold-leaf.