Skin Microrelief

Hold the back of a hand up close and the surface is plainly not flat. Shallow furrows cross one another at angles and enclose small raised plateaus, in a geometry that is present from birth and differs from one body site to the next. It is what lets skin stretch and fold in every direction without tearing, and it is why a magnified photograph of anyone's cheek looks like terrain.

The pattern changes with condition and with decades. On sites that take a lot of sun the furrows deepen and lose their crosswise arrangement, running increasingly in one direction. When the stratum corneum is short of water the raised fields lift at their edges, and light that would have reflected evenly scatters instead — which the eye reads as roughness and the fingers read as texture.

This is what “instantly smoother” is describing. An emollient or film-forming product settles into the furrows and softens the lifted edges, so the surface reflects more evenly within a minute. That is a real optical change, and it lasts exactly as long as the film does.

Changing the pattern itself is slow work that belongs to turnover and to the dermis underneath. Instruments that report roughness are usually reading this same network, which is why a reading taken half an hour after application and one taken at twelve weeks answer different questions. It is worth knowing which of the two a promise on the box is about.