_Preparing the Surface: Pouncing._--The surface is thoroughly cleaned and prepared with powdered pumice stone, or other suitable "pounce" (see pp. 167, 174). This being rubbed well into the actual part which is to take the size absorbs grease and slightly roughens[28] the surface. The surrounding parts are also pounced to prevent the gold-leaf from sticking to them later.
_Composition of the Ground or Size._ The chief [p147] substance in a "size" or raising preparation is generally some kind of earthy matter, to give it body. Other substances, having toughness and stickiness, are used to bind the earthy matter and prevent its breaking when the page is turned over or bent, and also to make the size adhere to the page and the gold-leaf stick to the size. Yellow or red colouring matter is often added. A preservative, such as oil of cloves--in a minute quantity--may be present: this will permit of the size being kept in a semi-liquid condition, in a closed jar.
The following recipe was given to me by Mr. G. Loumyer:--
"_Chalk (Whiting)._ _Oxide of Iron--1/2 grain._ _Glue (Carpenter's)--4 grains._ _Gum Arabic--2 grains._ _Water--50 grains._
_Melt the gum and the glue together in the water, then add the oxide of iron, and lastly put in enough chalk to make the whole a rather liquid paste. Apply to the parchment, which you have previously well rubbed with whiting, and, when dry, apply the gold-leaf with alcohol._"
_Mixing the Size with Water._--A little of the size, taken from the jar (see above), is put in the saucer with a few drops of water to soak for an hour or two. It is then rubbed down with a finger-tip, care being taken to mix it very thoroughly and to avoid making bubbles. The right consistency is judged by experience--it should be thick rather than thin.
It is essential that all the ingredients be present in their right proportions, and the mixture should be stirred every now and then. Otherwise the earthy [p148] matter settles down, and the sticky parts, remaining in solution above, are liable to be used up. What is left in the saucer after use is apt to be deficient in its sticky parts, and it is best thrown away. Take out of the jar only what is required at the time, and mix a fresh lot the next time.