Liquid Foundations

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Liquid foundations are also used to even out skin tone. They are heavier though than a pressed powder foundation and can provide more coverage.

Liquid foundations also use pigmentary TiO2 and iron oxides to provide color. The same ratios used in pressed powders apply to liquid foundations. An American shade is 10-12% pigmentary TiO2 and iron oxides (7% TiO2, 3% yellow iron oxide, 1.75% red iron oxide, and 0.2% black iron oxide). For much darker shades you would use much less pigmentary TiO2 (such as 1%) and a  more yellow, red, and black iron oxide. A Japanese shade contains more TiO2 than an American shade, ~10% TiO2. Though the percentage of each pigment will be different in each shade, you want the overall percentage of TiO2 and pigments to be the same for each shade so each will have the same feel.

Instead of using untreated TiO2 and iron oxides, which are hydrophilic, it is much better to use treated pigments. Treated pigments are easier to incorporate into oils, esters, and silicones. However, it is even better to use pigmentary dispersions than to make your own pigment grinds. The pigment in the dispersions are already well dispersed and the particle size is made small so that the color is more intense. Smaller particles provide for increased light scattering from the increased surface area of the small pigment. Also, a higher concentration of pigment can be incorporated into a dispersion because of the surface treatment on the pigment and manufacturing of the dispersion. You also get less streaking in liquid foundations when all the pigments are wet out, especially the red. Dispersions help in many aspects.

Silicones are frequently used in liquid foundations because of the lubricous feel and slip they provide. Water in silicone foundations dry slower than oil in water foundations and have more play time. If you have water in volatile silicone though, the foundation will dry fast because the silicone evaporates as you rub it out on your skin. Water in volatile silicone foundations also feel lighter on the skin than traditional foundations that do not have volatile.

Sunscreen actives can also be incorporated into a liquid foundation if you want to claim SPF. Film former can be added for long wear. Microspheres can be added to reduce any shininess that remains after its applied not he skin. Microspheres can also improve the feel of the of the liquid foundation on skin by creating more slip and a silky feel.