Umber

Raw umber is a cool, greenish, dull brown. Burnt umber is a warm dark chocolate. Between them, plus lead white and black, they are the whole palette of a great deal of seventeenth-century painting. The so-called dead colouring or grisaille stage is often umber and white, with the colour glazed over it later.

It is the cheapest route to a convincing dark. A black darkens by removing light and reads as a hole; an umber darkens and stays a colour, which is why a shadow painted in umber looks like a shadow and a shadow painted in black looks like a cut-out. This is the single most useful piece of colour knowledge in this entire library and almost nobody applies it to screens, where 'dark grey' is nearly always a desaturated neutral and nearly always looks dead.

Van Dyke brown, a related and much-loved dark brown, is a different material. A bituminous earth full of organic matter, and it is notoriously unstable. It never really dries, it cracks, it fades, and paintings built on it have suffered badly. The lesson is worth repeating: the browns that come from iron are permanent and the browns that come from decayed organic matter are not.

Underpainting, shadows, hair, wood, earth, and the entire tonal structure of a lot of Baroque painting. Also the standard darkener for wood stains and for makeup.

In digital work the transferable rule is to build darks out of a colour rather than out of neutral grey. A near-black with a warm bias reads as shadow; a pure desaturated near-black reads as absence. Any interface that feels lifeless in its dark mode is usually making this mistake, and the fix is a few degrees of hue in the darkest tokens.