We sell both Water Based Dyes and Liquid Pigments and we are often asked which is the best to use.
Water based dyes are ideal for both melt and pour soap bases and bath bombs. They are water soluble and work well in both clear and opaque bases.
However, they will bleed. By this we mean if two different coloured soap bases are next to each other in stripes or layers for example, the colours will merge and mix over time. If you are looking to make soap in layers then do consider the use of pigments instead.
We recommend that only dyes are used in bath products (salts, bombs) as this will avoid any staining of the bath.
Pigments are also suitable for melt and pour soap bases but are really only suitable for opaque bases. If you use a pigment in a clear base the result will be hazy and give a grainy appearance. Pigments are supplied in liquid form and so you should shake the bottle before use to ensure all the colour has not sunk to the bottom. We do not recommend their use in bath products such as salts or bombs because the tiny bits of colour will stick in any scratches in the bath and possibly stain it.
Both are supplied in a concentrated form and can be further diluted with deionised water if required. You can always add more colour but you cannot take it away!
Using colours in salts can also give varying results in that the colour may not be as expected. Please do test first before launching any large scale manufacturing to ensure you will get the required end result. Test test test and test again is always the best advice.