Friday, September 10, 2010
Chemistry: Refractive index
This term is really relevant in mineral make-up fillers because sometimes we want to reflect a lot of light and other times we want to absorb it so we don't emphasize those fine lines in our skin! If you are using micas, for instance, you have a lovely refraction rate that makes that glitter and shine we like. If you're using iron oxides, you won't get that same effect as the refractive index is quite low. Micronized mineral make-up fillers are less refractive than the non-micronized versions. The higher the micron size, the more reflective and shiny the filler will be.
And it's relevant in hair care products! If you want shine to your hair, you'll want to choose ingredients with higher refractive index levels. Dimethicone has a higher level than cyclomethicone, so adding more dimethicone to an anti-frizz spray will increase the shine on your hair!