3734. To Regulate the Color of the Gilding

3734. To Regulate the Color of the Gilding. The gold upon the gilt article, on coming out of the solution, should be of a dark yellow color, approaching to brown; but this, when scratched (see No. 3709 (To Remove the Chalky Appearance of Silver afterPlating)), will yield a beautifully rich deep gold. If the color is blackish it ought not to bo finished, for it will never either brush or burnish a good color. If the battery is too strong, and gas is given off from the article, the color will be black; if the solution is too cold, or the battery rather weak, the gold will be light-colored; so that every variety of shade may be imparted. A very rich dead gold may be made by adding ammoniuret of gold (see No. 3725 (To Prepare Chloride of Gold)) to the solution just as the articles are being put in; or, what is better, add some sulphuret of carbon in the same way as for silver solutions (see No. 3710 (To Increase the Brightness of the Deposit)), which affects the color and appearance of the gold in the same way as it does the silver.

3735. To Improve the Color of Gilding'

3735. To Improve the Color of Gilding'. A defective colored gilding may be improved by the help of the following mixture: 3 parts nitrate of potassa (saltpetre), 11/2 parts alum, 11/2 parts sulphate of zinc, and 11/2 parts common salt, are put into a small quantity of water, to form a sort of paste, which is put upon the articles to be colored; these are then placed upon an iron plate over a clear fire, so that they will attain nearly to a black heat, when they are suddenly plunged into cold water. This gives them a beautiful high color. Different hues may be had by a variation in the mixture.

3736. To Electro-gild with Red Gold

3736. To Electro-gild with Red Gold. Gold having the red color of 14 carat gold may be deposited by the battery in the following manner: Prepare a solution of cyanide of copper by adding cyanide of potassium to a solution of sulphate of copper until the precipitate at first thrown down is redis-solved. Add to this a solution of cyanide of gold (see No. 3727 (To Prepare Cyanide of Gold)) in sufficient quantity to give, on trial, the desired color of gold deposit. "When using this solution, the positive electrode plate should be of gold of the same color as that desired to be deposited.

3737. Practical Suggestions in Electro-gilding

3737.    Practical Suggestions in Electro-gilding. According to the amount of gold deposited, so will be its durability. A few grains will serve to give a gold color to a very large surface, but it will not last. This proves, however, that the process may be used for the most inferior quality of gilding. Gold thinly laid upon silver will be of a light color, because of the property of gold to transmit light. The solution for gilding silver should be made very hot, but for copper it should be at its minimum heat. A mere blush may be sufficient for articles not subjected to wear; but on watch cases, pencil cases, chains, and the like, a good coating should bo given. An ordinary sized watch case should have from 20 grains to a pennyweight ; a mere coloring will be sufficient for the inside, but the outside should have as much as possible. A watch case thus gilt, for ordinary wear, will last five or six years without becoming bare. Small silver chains should have 12 grains; pencil cases of ordinary size should have from three to five grains; a thimble from 1 to 2 grains. These suggestions will serve as a guide to amateur gilders, many of whom, having imparted only a color to their pencil cases, feel disappointed upon seeing them speedily become bare; hence arises much of the obloquy thrown upon the process.