The safest way to find out whether the edge is dry or not is to blow upon it. If the lustre of the gold is dimmed for several seconds, the edge is still too moist, but if the cloud vanishes immediately the edge is sufficiently dry.
We can also determine by a careful easy burnishing whether the edge is dry enough to be worked further.
The burnishing should always be executed with a flat agate burnisher, and afterwards followed by a flat blood stone. The burnishing should be commenced by covering the edge with a piece of thin smooth paper that has been rubbed with wax.
First burnish the gold laid on slightly, afterwards continue with greater force.
By this the edge acquires a uniformly dull aspect but a strong union of gold and paper is thereby established.
Before beginning the real burnishing rub the edge with a soft rag upon which a small quantity of pure white wax has been rubbed. This thin film of wax renders the burnishing much easier because the burnisher is made to glide more readily and securely over the edge.
The burnishing must first be executed lightly and then with greater force.
The repairing of gilt-edges should be avoided as much as possible. Should it become, nevertheless, unavoidable, then moisten the spots to be repaired with the solution of albumen described above, lay on gold leaf, allow the spots which you wish to repair to become dry, rub off and burnish as usual.
In place of albumen solution, sulphuric ether can be used for repairing. The latter has the advantage of causing the spots so repaired to become dry immediately, but it causes a lighter spot to appear in the gilt-edge. Alcohol, lightly applied, can also be used for this purpose and with more security. The gilding of the hollow edge is produced in the same way as that of the level edge. In scraping, curved scrapers are used. To lay on the gold use the frame. Transfer the gold leaf from the gold cushion to the strings of the frame, then carefully bring these strings closer to each other, so that the gold leaf is no longer straight, but somewhat hanging down. Then transfer it to the sized edge.
To burnish give the hand press an oblique position, making the front of the press lay lower than the rear so that one half of the hollow edge has a more horizontal position, and burnish it with a flat burnisher in the same manner as the level edge. This being done, the remainder of the hollow edge is likewise treated at the same time, giving the press a different position. Only after the edge has been burnished on both sides with a flat burnisher, is the round burnisher (tooth) used to finish the hollow edge on its length.