The CMYK colour mixing process is one of the popular systems used today for mixing dyes and pigments. Its also the same colour model used in digital printing. It offers the widest range of reproducible colours using only the Cyan(turquoise), Magenta (cerise or fuchsia) and Yellow primary shades plus Black which in the print world is described as "K".
This set of 16 plastic coloured filters consists of four filters for each of the primary colours. One represents 100% colour saturation, one corresponds to 50% saturation and two equal 25%. The different saturations imitate what happens when pigments and dyes are diluted in water.
The mixing of these colours is called subtractive colour mixing.
When these plastic coloured squares are placed on a white background they act as filters that absorb one or more colours and any colour that is not absorbed (subtracted) is the hue which the eye can see. By varying the amount of each colour a full range of colours can be produced.
The filters can not exactly match up to all dye colours. There are too many variables in the real world, but for anyone interested in colour theory it will give you a good starting point and allow you to work out for yourself, the quantities needed to obtain the shades you need. The filters will also help you to see what the likely outcome might be when you are adding extra colours in to your dye recipes.