Besides pure gold leaf, gold alloyed with various metals to change its colour can be had. None of the alloys keep their colour as well as pure gold, and some of them, such as those alloyed with copper for red gold, and with silver for pale gold, tarnish very quickly. These last are not to be recommended.
For silver tooling aluminium leaf may be used, as silver leaf tarnishes very quickly.
When the gold is pressed into the impressions of the tools with the pad of cotton-wool, they should be plainly visible through it.
The pattern must now be worked through the gold with the hot tools. The tools are taken from the stove, and if too hot cooled on a pad as for blinding-in. The heat required to leave the gold tooling solid and bright and the impressions clear will vary for different leathers, and even for different skins of the same leather. For trial a tool may be laid on the pad until it ceases to hiss, and one or two impressions worked with it. If the gold fails to stick, the heat may be slightly increased.
If the leather is slightly damp from the preparation the tools will usually work better, and less heat is required than if it has been prepared for some time and has got dry.
Before using, the faces of all tools must be rubbed bright on the flesh side of a piece of leather. It is impossible to tool brightly with dirty tools. A tool should be held in the right hand, with the thumb on the top of the handle, and steadied with the thumb or first finger of the left hand. The shoulder should be brought well over the tool, and the upper part of the body used as a press. If the weight of the body is used in finishing, the tools can be worked with far greater firmness and certainty, and with less fatigue, than if the whole work is done with the muscles of the arms.
Large and solid tools will require all the weight that can be put on them, and even then the gold will often fail to stick with one impression. Tools with small surfaces, such as gouges and dots, must not be worked too heavily, or the surface of the leather may be cut.
To strike a large or solid tool, it should first be put down flat, and then slightly rocked from side to side and from top to bottom, but must not be twisted on the gold.
A tool may be struck from whichever side the best “sight” can be got, and press and book turned round to the most convenient position.
It is difficult to impress some tools, such as circular flower tools, twice in exactly the same place. Such tools should have a mark on one side as a guide. This should always be kept in the same position when blinding-in and tooling, and so make it possible to impress a second time without “doubling.” An impression is said to be “doubled” when the tool has been twisted in striking, or one impression does not fall exactly over the other.