Illumination: Paint dilution & mixing

Dilution

All paints (except ready-made gold paint) need to be diluted before you can use them. Tube paints are thicker than toothpaste and cannot be used without addition of water. Plaka type paints are thinner but also need dilution. For many purposes you also need to mix the colours to get the right shade.

The diluted paint should be so thick that one layer of it will cover a pencil line on a white paper. It should also be so thin that it flows out and doesn't make ridges. If you have mixed a special shade which you want to use again, put it in a small sealed container. But avoid this if you can. When diluted paint has been left unused for a few hours, the pigment will sink to the bottom so you need to stir it thoroughly before you use it the next time. It's best to paint everything that should be in that shade at once. The second best thing is to throw away any leftover paint and mix new the next time you work, though it may be difficult to get an identical shade.

Never dilute the paint in the original container. Adding water will make the pigment separate itself from the glue. The pigment will sink to the bottom of the bottle and lie there as a hard muck, very difficult to stir up evenly. Instead, mix up a small quantity of paint for the work you are doing, and discard anything that's left over when you finish for the day.

Mixing colours

Paints of the same brand and type are usually intermixable. Always take care not to compromise the integrity of the original colours. If you stir the red paint with a stick that has half a drop of yellow on it, the red will no longer be quite the same.

Put a small blob of each paint that you want in the mixing vessel and add some drops of water. Stir with a #3 or #4 flat brush and make sure you squash all the little blobs of thick paint. If you need to add more undiluted paint, put a blob on the wall of the vessel and gradually squash it into the diluted paint. If you simply drop the blob into the mixture, you may end up with a lump of undiluted, undissolved paint lying invisibly on the bottom, which may suddenly change the tincture if you happen to touch it with the brush while painting.

To see what a mixture really looks like, paint a square inch with it on a piece of scrap paper and wait for it to dry. It usually becomes a little lighter when it has dried. Adding black or white will not only make the colour darker or lighter, but will also make it less intense and more "greyish". This may be useful in some cases, because unmixed paints are often very bright, almost garish.

Most shades are easy to mix, but some may present problems. Purple, for example, is a mix between red and blue. But you must use a red colour that doesn't contain any yellow. The red paint used in the middle ages was "vermilion" which contains some yellow. If you mix it with blue, you will get brown. For purple, use "carmine" red instead.

Always wipe the lid and the upper edge of your paint bottles with tissue before closing them. Otherwise, you will get deposits of dried paint along the lid and bottle edge. Fragments of this will fall down into the paint and make it uneven and crunchy. Deposits of dry paint may also cause the bottles to be untight and let in air.

To keep the paint fresh (especially important with gold paint), you can keep the bottles standing upside-down. This will prevent air from getting in.