Lesson #3: How deep to carve? ...
(contributed by David Bull)
This is one of the most common questions posed by newcomers to printmaking, and there is a very easy answer - it depends! It depends ... on whether you will be printing with a baren, or a press ... on whether the paper will be wet, or dry ... and it depends on the size of the block, and the distances between the 'raised' (uncut) areas of wood.
Blocks that will be printed in a press with rolled-on ink can obviously be cut very shallowly, as no ink will touch the carved-out areas to cause blotches, but if the printing is to be done with brushed-on pigment, which smears everywhere over the surface, the carving depth becomes very important.
Here are some measurements from my most recent key block. This is a fairly typical 'ukiyo-e' type print, with black outlines around many areas. (The print is illustrated here).
In an open space of 1cm in width, the carving goes down to 0.7mm
2cm ... 1.3mm
3cm ... 2.0 mm
5cm ... 3.6 mm
10cm ... 4.5 mm
At no spot on the block has the wood been carved any more than 5.0 mm deep.
This is pretty shallow, and I have to add that ten years or so ago, I would not have been able to print from this block without creating many blotches on the paper. But I've learned to control the baren well, and it is now rare that I have to do any 'wiping' of prints that have contacted the ink where they shouldn't have.
Why carve so shallowly? It makes a very big difference in the brushing. If the vertical depth of the carved out areas is very large (more than 5mm or so), the hairs of the brush tend to get dragged across the relief lines at very sharp angles, and far too much paste and pigment is pulled from the hairs and deposited against the lines. It becomes quite difficult to avoid tamari, the blotchiness from paste building up on each line.
For smooth clean printing, with even impression and no tamari, the block should be as flat as possible, with only a small difference in level between the top of the lines (the original wood surface), and the bottom of the carved hollows. This means shallow carving. It requires very good baren control, and a good 'image map' in your mind of just where the carved areas of the block are (you can't see once the paper is in place), but the results are worth it ...
'Go deep!' OK in football ... not so good in printmaking ...