These technics, which are strange for us, are more than useful.
In a recent publication, Régine Frick on behalf of Premium Beauty, highlights the benefits of taking an interest in optical phenomena and recalling their interest in cosmetics.
These approaches have already led to interesting advances that I allow myself to remember. This is for example the “soft focus”, effect, now become “Blur”. This approach consists in the use of particular pigments having the diffracting light property on the skin surface. This leads to a significant decrease in the skin micro relief perception, resulting in a smooth and flat appearance. This concept was originally proposed by Japanese teams in the late 1980’s (Nakamura and All, Paper 23, Table 21, 14th IFSCC Congress 1986) which later became generalized with other varieties of pigment by a-lot of brand. If, initially, the pigments consisted mainly on specific forms, such as silica beads fixed on mica platelets, the technology has progressively proposed other substances such as silica or PMMA beads, boron nitride or even closer to us, with the elastomeric silicone powders functioning such as a sort of light trap. Even more specific approaches have been proposed as a combination of a soft focus charge and a fluorescent substance, completing the diffraction of a complementary reflection (EP1099437A1).
As a reminder, just a few words regarding the refractive index assesment which allows to finely regulate the notions of transparency and shine in formulation, both in make-up and for other families of products such as transparent emulsions.
Finally, just a word for the research done on transparency. Nobody talks about it yet! But still.