MARBLING

A sponge with large holes is dipped in potash, sulphate of iron, or some other deep coloured dye, and lightly applied over the surface of the leather so that parts of it corresponding to the holes in the sponge are left untouched; or the first application of colour may be made evenly over the leather and the marbling worked, as described, in a second application.

Many varieties of pattern can be obtained by moving the sponge in different ways. Leather may be bought ready marbled by a gelatine process.

TREE MARBLING

The leather is first lightly pasted over, and drops of water, more or less large, are scattered upon it by jerking the handle of a small couch-grass whisk full of water against the left wrist held a few inches from the surface of the leather. A very little colour is then taken in the brush and jerked in the same manner over the drops of water, with which it will partially mix and give the effect of roots branching out in all directions. Variety can be obtained by applying the water with a sponge instead of the brush, and the colour in large drops over the whole or certain parts only of the field, or by using dyes of different colours which give curious effects in combining. After applying the dye, the surplus moisture is absorbed with blotting-paper.

The leather may be bleached to a light tint by means of an oil-paint brush dipped in decolorant[12]; the bristles of the brush are pushed back with the finger and when released jerk the acid in fine drops over the surface. The leather must be freshly and thoroughly damped so that the outline of the bleaching shades off into the ground.

[12] See page [71].

SPRINKLING

Sprinkling is done with a rather close iron grating and a long narrow brush like a plate-brush. The dye is prepared on a flat plate and the brush dipped in it, the superfluous liquid being removed against the edge of the plate. The brush is rubbed backwards and forwards on the grating held horizontally a few inches above the leather over which it scatters a fine shower of the dye. Should the colour froth on the grating, the brush must at once be rubbed upon

oiled paper. Sprinkling may also be done with a vaporiser for fixing drawings, but it is difficult to get a sufficiently fine shower so that the drops do not merge into each other.