I always think of mineral make-up as the melding of science and art in a beautiful product you can wear on your face. The bases represents the science; the colours represent the art.
Sometimes the colour choices can seem overwhelming at times. Do I choose an iron oxide, an ultramarine, a hydroxide, a mica, a dye? What are the differences between them?
The two main categories of colourants are dyes and pigments. Dyes are water soluble and tend to come in liquid form. Pigments are water insoluble and tend to come in powdered form.
In the category of dyes we find liquid colourants like Labcolours and powdered colourants like the FD&C water soluble colours. These are suitable for water based products and bath bombs. You can use these for mineral make-up, although I can't give you any advice on the liquid colours as I've never used them before. The powdered FD&C colours are quite vibrant and will give you some fantastic colours. If you're looking for a matte, powdered red, this is probably the only way to find it. (The other alternative for a matte, powdered red is carmine.)
In the category of pigments we find the bulk of our colours for mineral make-up, and these ingredients will be the focus of my next few posts. Pigments are not soluble in water and are suitable for soaps, anhydrous products, and cosmetics.
Colours can be organic or inorganic. This does not mean they are "organic" in the sense of being grown without pesticides or from nature or whatever other definition people use for this word. If a colour is listed as organic, it means it contains a carbon atom (click here for more information on organic chemistry). If a colour is listed as inorganic, it means it does not contain a hydrocarbon group (a carbon-hydrogen group).
There are two pigments that may be organic in nature - meaning, they do contain a hydrocarbon group.
Lakes: Water soluble colourants are adhered to a water insoluble ingredient (like a metal salt) so they will remain insoluble in water. These are mostly the FD&C colours made water insoluble in a powdered form. They are great for soap or oil based products. Lakes tend to be less stable than other pigments in light but are stable in heat and when faced with a lot of chemical processes (for instance, acid or alkaline environments).
Carmine: Carmine is a bright red colour made from the bodies of the cochineal beetle. The colour is produced by carminic acid the beetle uses as a defence mechanism. It can be water or oil soluble, depending upon the preparation. It can be listed as "natural red" at times, and is approved for mineral make-up and food preparations.
A lot of people shy away from using carmine because of its animal origin. If you are keeping kosher or are vegan, this is definitely an ingredient to avoid. And it can cause allergic reactions in some people.
Join me tomorrow for fun with inorganic pigments!