Wet Drawing Techniques: Ink, Wash, Watercolour, Gouache, Tempera
Water-based media share a diluent but differ in binder and opacity, and that difference drives every exam decision: what can be glazed, what can be overpainted, and where the white comes from.
Ink and wash
- Ink (tinta china) uses shellac or acrylic binder and is permanent when dry; diluted with water it becomes a grey wash. Techniques: hatching, dry brush (pincel seco), reserve with wax or masking fluid, splatter (salpicado).
- Wash (aguada) is judged by evenness: a flat wash is laid in one pass with the board tilted, a graduated wash adds diluent progressively, and a damp paper edge prevents hard drying lines.
Watercolour
- Transparent: white is the paper, so plan reserves before the first stroke.
- Wet-on-wet gives soft diffusion, wet-on-dry gives crisp edges; a glaze (veladura) is a single transparent pass over a bone-dry layer.
- Know pigment behaviour: staining colours (phthalo) resist lifting, granulating colours (ultramarine, burnt sienna) settle into the grain.
Gouache and tempera
- Gouache is opaque watercolour: gum arabic with white or chalk extender. It rewets, allows light-over-dark correction, dries matte and usually lighter than it looks wet. Thick layers crack.
- Tempera binds pigment with egg emulsion or a modern polymer variant; it dries fast, is luminous and cannot be reworked, so layers must be thin and deliberate.
Worked example
Paint a sky with clouds in watercolour. Reserve the cloud shapes with masking fluid or clean water, wet the paper, drop warm yellow near the horizon and cool blue above so the pigments merge, let it dry completely, then glaze one cool transparent layer over the shadow planes of the clouds. Reasoning: the light comes from unpainted paper, the sky is a single diffusion, and the cloud modelling is a glaze, never an opaque white correction.
Marks-losing traps
- Reworking a half-dry wash produces backruns and cauliflower edges (florituras).
- Mixing three or more pigments in one puddle creates mud; keep to two.
- Using opaque white for highlights in watercolour, which destroys transparency.
- Judging gouache colour while wet; it dries lighter.
- Overlaying too many glazes, which flattens the paper's luminosity.