I came across this while I was searching for IR and NMR spectroscopy cheat sheets (I found them here [IR] and here [Proton NMR], for those interested!).

It’s well illustrated and well explained. The author, a chemistry PhD, shows how companies like Almay use emulsions and solubility to create cool effects like a cream going from white to skin toned!

By taking advantage of the fact that some things dissolve in water and some in oil, the makeup manufacturers can hide the skin toned pigments inside water tinted white with titanium dioxide!

(Also there’s no “smart” in the smart shading…a cream can’t tell what colour your skin is…yet!)