g. Mix 20.3 fluidounces of the glue solution with 1.41 ozs. of lampblack. For gray add sufficient zinc white to produce the desired shade. The rest of the glue solution is mixed with 6⅓ ozs. of zinc white.
h. Mix 10 fluidounces of the glue solution with 0.8 oz. of umber, 10 fluidounces of the glue solution with 0.8 oz. of bole, 10 fluidounces of the glue solution with 0.8 oz. of ochre, and the rest with 4½ ozs. of zinc white.
i. For enamels mix 20.3 fluidounces of the glue solution with 1 oz. of ultramarine, and the rest with 6⅓ ozs. of zinc white.
k. Mix 20.3 fluidounces of the glue solution with 1.41 ozs. of chrome green, and the rest with 6⅓ ozs. of zinc white.
For imitating mother-of-pearl veneers, 0.42 oz. of silver bronze, which need not be genuine, is ground with a little glue solution or water and intimately mixed with the above solution of glue. The bronze powder must not be in a dry state when stirred into the glue, as lumps would be formed and the veneers become spotted. In place of bronze, essence of fish scales, which is of course far more costly, can be used.[2] The glue solution thus prepared is then compounded with different aniline colors according to the tint desired.
[2] This preparation is also known by the name Essence d’Orient. The material for its production is furnished by a small white fish very common in the rivers of continental Europe. It accompanies the scales of this fish, and is detached when the scales are triturated for a considerable time and thrown into a vessel of water. To collect the essence the water is poured off upon a fine hair sieve, which retains the scales and allows the water and the product sought to pass through. The latter sinks to the bottom, and is obtained pure by decanting the water. A little ammonia is added to prevent decomposition.
a. For yellowish veneers no coloring matter is required, or the desired shade is obtained by an addition of some solution of picric acid.
b. For colorless veneers or those of slightly reddish tints a smaller or greater number of drops of a concentrated solution of fuchsine are added in order to counteract the yellowish color of the glue solution. For these imitations of mother-of-pearl veneers, concentrated solution of gelatine compound with 15 per cent. of glycerine can be employed, especially when essence of fish scales is used.
c. For blue, the glue solution is compounded with bleu de Lyons, care being had not to use too much, as otherwise the imitation becomes indistinct. The proper degree of coloring is tested by allowing a few drops of the colored glue solution to fall upon a glass plate.
d. For red, solution of fuchsine or carmine is used, the latter being obtained by dissolving commercial carmine powder in alcohol.