Click here for a complete list of the Cosmetic Formulation basics series.
Foundation or skin colorants are designed to enhance the color and appearance of the face. They are also used to impart a smooth surface for which other color products can be added.
What foundation does
Foundations are available in a variety of forms including emulsions, anhydrous cakes, sticks, and pressed or loose powders. They are composed of colorants that are applied to the skin to create a continuous even tone. The colorants are able to smooth out the surface of the skin and scatter light to modify the color. Some foundations have additional ingredients that can provide benefits such as skin moisturization, sun protection and anti aging.
How foundations work
A foundation formula is composed of a variety of compounds to impart benefits. The primary functional ingredient is a coverage pigment and coloring pigments. Additionally there are filling ingredients, fragrances and depending on the formulation type emulsion ingredients, preservatives, antioxidants, and even UV protectants.
The primary coverage pigments in foundations are Titanium Dioxide, Zinc Oxide, and Kaolin. These produce a white color which is able to scatter light and reduce the skin’s natural color. Some of these ingredients have the added benefit of being UV protectants. However, foundation is not applied in a manner that can provide significant sun protection so it is rare that any foundation formula would claim it.
Filler ingredients include talc which can help spread the primary coverage pigments around on the face. They make the product easier to use. Filler ingredients include talc, mica, sericite and specialty fillers such as bismuth oxychloride.
Color pigments including red, yellow, and black iron oxides can be mixed to create a shade that matches any skin tone.
Fragrances are often incorporated in foundations because consumers generally like pleasantly fragranced products. If the formula is going to be an emulsion ingredients like emulsifiers, water, and preservatives are also included.
Here is a typical foundation formula (click to enlarge)