The luminous color in Rembrandt’s portraits, Vermeer’s interiors, and Leonardo’s flesh tones all share a common technique: glazing. Rather than mixing all the color at once on the palette, glazing builds color through multiple transparent layers, each drying before the next is applied. The result has a depth and warmth that direct painting cannot replicate.

What Is a Glaze?

A glaze is a thin, transparent layer of oil paint applied over a dry underlayer. The glaze is so thin that light passes through it, reflects off the underlayer beneath, and returns through the glaze — creating the impression of light coming from within the paint. This is fundamentally different from mixing colors on the palette, where you see only surface reflection.

Materials for Glazing

  • Transparent pigments — Alizarin Crimson, Phthalo Blue, Quinacridone, Transparent Oxide Red. Opaque pigments like Cadmium Yellow or Titanium White do not glaze effectively.
  • Glazing medium — linseed oil, Liquin (alkyd medium, dries faster), or a commercial glazing medium. This extends the paint and increases transparency.
  • A dry underlayer — the layer below must be completely dry before glazing. This is why oil glazing requires patience.

The Glazing Process

  1. Establish your value structure first — paint the entire composition in light and dark values using a neutral, opaque underpainting (grisaille). This can be done in grey, brown, or raw umber.
  2. Let it dry completely — depending on the medium, this takes days to weeks.
  3. Mix your glaze — take a transparent pigment and mix with glazing medium until almost waterlike in consistency. It should be barely colored when spread thin.
  4. Apply with a soft brush in smooth, even strokes
  5. Wipe back where needed — you can lift glaze from highlights while wet using a clean dry brush or cloth
  6. Repeat — build color gradually over multiple layers, always letting each dry completely

Building Flesh Tones with Glazes

The Old Masters built portrait flesh through layers: a warm reddish-brown underpainting, then cool grey-green mid-tones (verdaccio), then warm flesh glazes on top. The green beneath the warm glaze creates the subtle, complex color of real skin. It sounds counterintuitive but the result is extraordinary.