Pigment, Binder, Support
Paint consists of a pigment held in a binder that sticks it to a support. The pigments are largely shared. The Binder decides almost everything about how the picture is made.
| Medium | Binder | Drying | What it permits | What it forbids |
|---|---|---|---|---|
| Fresco | Lime plaster | Hours | Permanent wall painting | Revision after setting |
| Tempera | Egg yolk | Minutes | Precise line, clear colour | Soft blending |
| Oil | Drying oil | Days to weeks | Blending, glazing, revision | Speed |
| Watercolour | Gum arabic | Minutes | Transparency, luminous whites | Covering a mistake |
| Acrylic | Polymer emulsion | Minutes | Fast layering, any support | Slow blending |
Fresco imposes a schedule
In buon fresco, pigment binds chemically to wet lime plaster. The paint becomes part of the wall itself.
The painter must finish before the plaster sets. Work is therefore divided into giornate, or day-pieces. Corrections require cutting out the dry plaster entirely.
Oil changes what a picture can be
Oil paint was not invented by Jan van Eyck. However, fifteenth-century Netherlandish painters perfected its use.
Its slow drying time permits new techniques:
- Blending: smooth transitions worked wet into wet.
- Glazing: luminous depth through transparent layers.
- Revision: changing composition over weeks of work.
- Deep, saturated darks: carrying dense loads of pigment.
Support matters too
A Panel is rigid, stable, and heavy. Canvas is light, flexible, and portable.
Common pitfall: treating the medium as a technical detail. The medium dictates what a style can achieve. A tempera panel cannot produce the soft transitions of a Venetian oil painting.