One-point Lesson : Consistent Colour
Lesson #19: Maintaining consistent colours
The 'mix on the block' method of preparing a Japanese woodblock for printing is a very effective way of controlling the depth of colour in the finished print. For each and every impression, a small bamboo 'whisk' known as the tokibo (or hakobi) is used to transfer the desired amount of pigment over to the block. A suitable amount of paste is then dabbed on the block, and the two components are mixed together and spread out by the brush.
If a deep tone is desired, more pigment is transferred from the bowl to the wood, and if a light tone is wanted, less pigment ... But once the desired colour is decided - it is sometimes not such a simple matter to keep it the same from print to print. You must watch the prints, and adjust your 'dab' of pigment as necessary.
One way to greatly ease the process and to help ensure consistent colour, is to use a large brush - the larger the better. Brushes hold a lot of pigment and paste up in their hairs, and when a large brush is used, you are less dependent on how much you dab on the block each time; the large reservoir of pigment serves to maintain consistency. Of course, if you consistently dab on a lot, the colour will slowly deepen, and you have to be careful to avoid this, but the large brush helps avoid wild swings from print to print.
It is perhaps sort of like steering a large oil tanker, as opposed to a sports car. In each case, adjustments to the 'steering wheel' have dramatically different effects.
Be aware that when using a large brush, it will take a number of impressions to reach the point where the brush is carrying a full load of pigment. One common way for printers here in Japan to get started with a run is to dab pigment and paste on the block, swish it around with the brush thoroughly, and then dab again, swish again, dab again, swish again ... all without putting any paper down and taking any impressions. After three or four of these 'false' impressions, the brush will be loaded and ready, and you can start printing your edition with some assurance of consistent colour.
Big brushes can be expensive, but they are essential to producing even and consistent work.