Yellow ochre, burnt sienna, Venetian red: three tubes that cover half of painting
These three earths were the entire palette of European oil painting for two centuries, and they still do more work than any other group in watercolour. The reason is that they mix with everything without sullying it, and they dry to exactly the value they showed while wet.
Burnt sienna — Semi-opaque warm earth, settles fast.
| Pigment | Parts | Hex |
|---|---|---|
| Yellow Ochre | 4 : 10 (40%) | #C99442 |
| Burnt Sienna | 3 : 10 (30%) | #9A5A32 |
| Venetian Red | 2 : 10 (20%) | #A6472F |
| French Ultramarine | 1 : 10 (10%) | #2E4A7D |
Mixing notes
| Sand Yellow ochre alone, diluted. Nothing else gives this colour; anything you add makes it something else. | 4 yellow ochre at 20% load | #D4B27A |
| Terracotta The pair that makes roof tiles. At 70% load it is a wall; at 30% it is skin in shade. | 3 burnt sienna + 1 venetian red | #B4633A |
| Earth olive The cheapest useful green in watercolour. Ochre and ultramarine, nothing else, no skill required. | 3 yellow ochre + 1 ultramarine | #7C7A46 |
| Warm dark A dark that stays warm. This is what you use instead of black for the underside of anything. | 2 burnt sienna + 2 yellow ochre + 1 ultramarine | #4E3A2E |
| Brick shadow Venetian red is a cool, slightly opaque red; paired with ultramarine it makes a purple-brown that reads as shade on masonry. | 3 venetian red + 1 ultramarine | #7B4638 |
- Paint the yellow ochre square first, at full strength and at 20% load, side by side. The value difference between them is the whole lesson about load.
- Mix the terracotta at 70% and at 30% and paint both. Note that the hue barely changes while the value moves two full steps.
- Mix the earth olive with a palette knife, not a brush, so you can see how much the two pigments resist each other.
- Add ultramarine to each of the first four mixes, one part at a time, until the colour stops being recognisable as its original. Mark that point.
- Paint a 10 x 15 cm study of a single terracotta pot using only these four pigments and no black.
- Judge the whole sheet dry. Yellow ochre and burnt sienna shift value by up to a full step as they dry; Venetian red barely moves.
- Cover the sheet with a clear acrylic medium if you want the swatches to stay accurate — earth pigments are the most lightfast on the palette and are worth preserving.
Why earth pigments behave so well
Ochre, sienna and Venetian red are all iron oxide pigments — essentially rust with different amounts of water bound into the crystal lattice. That shared chemistry is why they mix with each other, and with ultramarine, without the muddying you get when you combine organic pigments with different particle shapes.
They are also the most lightfast group available. A watercolour painted entirely with earths will outlast the paper it is on. This is why they are the correct choice for anything meant to be archival — studies, commissions, work that will be framed under glass for decades.
The value shift you must plan for
Yellow ochre and burnt sienna both lighten by up to a full step as they dry, because their particles are coarse and the water film that darkens them while wet disappears. Venetian red, being finer and slightly opaque, barely shifts.
Practically: mix earths one value darker than you think you need. This is the opposite of the rule for phthalo and quinacridone pigments, which darken slightly as they dry because they are so staining.
Ochre plus ultramarine
Yellow ochre and French ultramarine in a 3 : 1 ratio make a serviceable olive green with no skill involved — the two pigments do the work. Push to 5 : 1 and you get a warm khaki; push to 2 : 1 and you get a cool, slightly granular blue-green that reads as conifer.
The mix works because ochre is opaque and ultramarine is transparent and granulating. The ochre provides body and the ultramarine provides the speckle, which is why this green looks like vegetation rather than like a painted shape.
What matters
- Iron oxide earths mix with everything, including each other, without muddying.
- They are the most lightfast group available — the correct choice for archival work.
- Ochre and burnt sienna lighten by up to a full step as they dry; mix one value darker.
- Yellow ochre 3 : 1 with ultramarine makes a free olive green; 2 : 1 makes a conifer blue-green.
Handling note — Technique notes only. Follow the manufacturer's safety data sheet for pigment handling and disposal.