Dry-Down

Dry-down is the period between applying a product and the moment it has finished changing on skin. Water and volatile solvents evaporate, films set, powders settle, and what a formula feels like at the end can be quite different from how it felt going on.

It matters for two practical reasons. The first is layering: a product applied over a layer that has not finished drying is more likely to pill, slide or dilute, which is why waiting a short time between steps solves so many texture complaints. The second is judgement — a sunscreen or moisturiser that feels greasy for the first minute may be perfectly comfortable three minutes later, and a product dismissed too early was never really tested.

• Volatile-heavy formulas, such as long-wear makeup and some sunscreens, have a fast and obvious dry-down.
• Rich creams and balms have almost none; they stay much as they land.
• Humid weather slows evaporation, so the same product can behave differently by season.

There is no fixed number of minutes worth quoting, since it depends on the formula, the amount and the air around you. Watching how a product settles is a more reliable guide than a rule.