The Palette/green/Grown
Sap green
Boiled buckthorn berries, stored in a pig's bladder, and gone within a generation of being painted.
Also called buckthorn green · vessie · bladder green
- Hex
- #507D2A
- RGB
- 80, 125, 42
- First used
- Medieval Europe
- From
- Northern Europe
What it is
A mixture of flavonoid colourants from ripe buckthorn berries, with alum.
How it is made
Ripe berries of Rhamnus are crushed and the juice boiled down with alum to a thick syrup. It never fully solidifies, so it was traditionally stored in an animal bladder tied at the neck: you pricked the bladder with a pin when you needed some, which is where the name 'bladder green' comes from.
It is a dye rather than a pigment, so it stains rather than covers, and it has no real body. In watercolour that is a strength; in anything else it is a problem.
Sap green, Pigment made by precipitating a dye with an inert binder, or mordant. Wikipedia's description, not ours.
The history
It was the convenient green of manuscript illumination and later of British watercolour, because it required no grinding, no lake-making and no careful handling. Convenience is why it was used and permanence is why almost nothing survives looking as it did.
Sap green fades comprehensively, and it fades unevenly, which is worse. A landscape painted with it does not go pale. It goes blue, because the yellow component of the green leaves first and the blue underneath or alongside it stays. Any old watercolour with disconcertingly blue trees has probably lost its sap green.
Modern tubes labelled sap green are mixtures of permanent pigments (usually a phthalo green with an earth yellow) matched to the traditional colour. They are a different material with the same name, which is now true of more than half the colours on a paint chart.
Where it is used
Manuscript illumination, map colouring, and British and Dutch watercolour landscape from the seventeenth century.
The general point is a warning about mixtures that fade at different rates. Any colour built from two components will not fade towards grey, it will fade towards whichever component is more permanent. This applies directly to printing, where a purple built from magenta and cyan will go blue as the magenta goes first, and to any brand colour built as a mix rather than a spot.
Go and look at it
Eighteenth-century British watercolours with blue foliage
Tate Britain and the V&A, London
The trees were green. The yellow half of the mixture has gone.
How it behaves
- Made of
- A mixture of flavonoid colourants from ripe buckthorn berries, with alum.
- Opacity
- Transparent. It stains rather than covers, so it can be glazed over another colour.
- Lightfastness
- Fugitive. It leaves. Work made with it is already less than it was.
- Fades badly, and fades unevenly. The yellow goes first and the picture turns blue.
- Never dries hard; traditionally stored as a syrup in a bladder.
- Every modern tube of this name is a substitute mixture.
The numbers
All derived from the hex, never typed beside it
- HEX
- #507D2A
- What a browser and a design file want.
- RGB
- 80, 125, 42
- The same three numbers in base ten. Light, not ink.
- HSL
- 93°, 50%, 33%
- Hue, saturation, lightness, how a person describes a colour.
- CMYK
- 36, 0, 66, 51
- Arithmetic only. A real separation depends on the press, the paper and a profile.
- LAB
- 48, -30, 39
- Perceptual. L* of 48 is how light this actually looks, which HSL gets wrong.
This hex is an approximation, and a page about pigment has to say so. Sap green is a substance. A ground mineral scatters light from thousands of separate grains at slightly different angles, and no single sRGB value is that event. It is a flat average of a photograph of it, and the real thing is outside what a screen can emit. Use the number to specify a screen colour. Do not use it to judge the pigment.
Where it sits on the wheel
Hue 93°
Its opposite, by the diagram
The arithmetic opposite, 180° round in HSL. Useful, and not the same as the opposite a painter mixing pigment would name, that wheel was built for paint.
Lighter and darker
Towards white
Mixing with white does not only lighten, it dulls and cools. This is why a pale tint of a brand colour so often looks chalky, and why a designed light shade beats a generated one.
Towards black
Mixing with black kills the hue as it darkens. A better dark is usually the colour plus its neighbour round the wheel, which is what every painter does instead.
Can you set type on it
Handgloves
White on it
4.87:1 · AA
Handgloves
Black on it
4.31:1 · Large text only
Handgloves
It on paper
4.63:1 · AA
Handgloves
It on ink
3.75:1 · Large text only
4.5:1 is the floor for body text and 3:1 for large text, by WCAG. Treat it as a minimum you may not go under rather than as a target: plenty of pairs pass at 4.6:1 and are still unpleasant to read for a page, and the checker will not tell you that.
Read more, elsewhere
Colours next to this one
Next, in time
Bistre
Boiled soot from a wood fire: the drawing ink of Rembrandt and Claude, and it fades to nothing given a window.
Back up
Foundations · Colour·green·Grown