To begin printing, one takes first the key-block, laying it upon a wet sheet of unsized paper, or upon wads of wet paper under each corner of the block, which will keep it quite steady on the work-table. A batch of sheets of printing paper, prepared and damped as described in Chapter V (Preparation Of Paper, Ink, Colour, And Paste For Printing. Paper), lies between boards just beyond the block. The pad lies close to the block at the right on oily paper pinned to the table. To the right also are a dish or plate on which a little ink is spread, the printing brush (broad for the key-block), a saucer containing fresh paste, a bowl of water, a small sponge, and a cloth. Nothing else is needed, and it is best to keep the table clear of unnecessary pots or colour bottles.

When these things are ready one should see that the paper is in a good state. It should be rather drier for a key-block than for other blocks, as a fine line will print thickly if the paper is too damp and soft. In fact, it can scarcely be too dry for the key-block, provided that it has become perfectly smooth, and is still flexible enough for complete contact with the block. But it must not be either dry or damp in patches.

If the paper is all right, one lifts off the upper board and top damping sheet, placing them on the left, ready to receive the sheets when printed.

The key-block, if quite dry, must be moistened with a damp sponge and then brushed over with the broad printing brush and ink. If a grey line is wanted the brush should be dipped in a little of the paste and scarcely touched with ink. For a pale grey line the key-block also must be well washed before printing. Even if the line is to be black a little paste should be used. This is best added after one has brushed the black ink on to the block, not mixed with it beforehand. The ink and paste are then broken together smoothly and completely over the whole surface of the block. The last few brush strokes should be of the full length or breadth of the block and be given lightly with the brush held upright. The inking of the block must be thoroughly done, but with no more brushing than is necessary to spread the colour equally. When properly charged with ink the block should not be at all wet, but just covered with a very thin and nearly dry film of ink and paste.

No time should be wasted in lifting the top sheet of printing paper on to the block, placing first its right corner in the register notch, and holding it there with the thumb, then the edge of the paper to the other notch, to be held with the left thumb while the right hand is released to take up the baren (fig. 21). Beginning at the left, the baren is rubbed backwards and forwards, a full stroke each time, to the outside limits of the block, with a moderate, even pressure, moving the stroke in a zigzag towards the right end of the block (fig. 22). Once over should be enough. A second rub makes heavy printing of the finer lines. Then the paper is lifted from the block and placed on the board to the left.

Fig. 21. - Manner Of Holding The Paper

Particular attention must be given to the careful placing of the paper home in the register notches, and to holding it there until the rubber has gripped the paper on the block.

Sheet by sheet all the printing paper is passed in this way over the key-block, and piled together. There is no fear of the ink offsetting or marking the print placed above it. As the work proceeds the block will give better and better impressions. Spoiled or defective impressions should be put together at the top of the pile when it lies ready for the next printing, for the first few impressions are always uncertain, and it is well to use the defective prints as pioneers, so as not to spoil good ones.

Fig. 22. - Manner Of Using The Baren

When the block has been printed on the whole batch, the sheets should be replaced at once between the boards before one prepares for the colour impressions. Usually the paper will be too dry for colour by this time: if this is so, the damping sheets should be moistened and put in again as before; one to each three printing sheets. In a minute or two they will have damped the paper sufficiently and must be taken out, leaving the printing sheets to stand, between the boards, ready for the first colour-block.