Before proceeding to the details in the work of finishing, a few preliminary observations may be made.
Blind tooling is the ornamenting of leather with tools without the application of gold. It might also be correctly described as matt tooling. Its peculiarity and beauty consist in its rendering the tooling on the leather in a darker tone. Blind tooling may be executed upon leathers of any colour, but its full decorative effect is seen only upon light colours, especially upon undyed calf and pig-skin and also upon coloured unpolished calf.
To produce the deepest and most uniform tone it is necessary to damp the leather previous to tooling. As it is well that the whole surface to be tooled should retain some moisture it is advisable to damp it evenly with a sponge on beginning the work.
The simplest tools are, as already mentioned, the fillets, which may be single, double, or triple, with lines of equal or different thickness.
The design is carefully traced with dividers, folder, and rule, and the heated tools run along the rule. Before applying the tool, which should be only moderately heated, the line previously marked out should be damped with a suitable brush. The instant the moisture has been absorbed by the leather, the tool should be applied. There should be no hissing, as the tool should be only lukewarm for the first application. The roll must touch the leather at the beginning without any uncertainty and the line made at once and without stopping, as otherwise a darker shade would appear in places.
Each time before using the roll it is passed over a well-greased piece of leather.
The impression should appear uniformly brown; if it is lighter at any part, it has not been sufficiently damped; if darker at another place from the beginning, then that part was too damp. Success depends before everything else upon uniform damping of the leather and correct heating of the tool.
With ordinary cleanliness and care, complete success is assured in this method of finishing.
After the surface of the leather has again become dry in all places, the whole design is again gone over, but this time with the roll a little hotter, at the same time rubbing the roll well with the greased cloth. If there had been unevenness in the depth of colour before, it will hardly be possible to remedy it now, for the light places remain so and the dark ones become even darker.