Part III · Craft, genres and media · Chapter 22 of 31

Value, light and form

Value — lightness and darkness — does most of the work in a picture. If the values are right, the colour can be surprisingly free. Squint at any masterpiece and you will see a few big, clear value shapes.

The Calling of Saint Matthew by Caravaggio — **The Calling of Saint Matthew**, Caravaggio (1599–1600). Oil on canvas. San Luigi dei Francesi, Rome. Source: Wikimedia Commons · CC0

Girl with a Pearl Earring by Johannes Vermeer — **Girl with a Pearl Earring**, Johannes Vermeer (c. 1665). Oil on canvas. Mauritshuis, The Hague. Source: Wikimedia Commons · Public domain

The Milkmaid by Johannes Vermeer — **The Milkmaid**, Johannes Vermeer (c. 1658). Oil on canvas. Rijksmuseum, Amsterdam. Source: Wikimedia Commons · Public domain

Light on form

Light falling on a rounded form creates a predictable sequence: highlight, light, halftone, core shadow, reflected light and cast shadow. The core shadow — where the form turns away from the light — is the key to making things look solid.

Keep lights and shadows separate. Reflected light in the shadows is always darker than the halftones in the light. Beginners often make it too bright and the form falls apart.

Designing with value

Plan a picture in three to five values. Caravaggio and Rembrandt used chiaroscuro — strong light against deep shadow — to direct the eye. Seurat's conté drawings build whole figures from soft value shapes with no outlines at all.

Make a quick thumbnail in grey before you paint. If it reads at the size of a postage stamp, it will read on the wall.