The Palette/brown/Taken from an animal
Sepia
Cuttlefish ink, and the reason every old photograph in the world is brown.
- Hex
- #704214
- RGB
- 112, 66, 20
- First used
- Classical antiquity as ink; as an artists' colour from around 1780
- From
- The Mediterranean, and later Ceylon and the Adriatic
What it is
Melanin from the ink sac of the cuttlefish, Sepia officinalis, treated with alkali.
How it is made
The ink sacs are removed, dried, and the contents dissolved in a dilute alkali, then precipitated with acid, washed and dried. The result is a fine brown-black powder that redissolves easily, which makes it a natural drawing ink and watercolour.
Jacob Seydelmann in Dresden is usually credited with developing the concentrated artists' version around 1780, which is when sepia stopped being an ink used for writing and became a colour used for pictures.
Sepia, Shade of brown derived from the common cuttlefish. Wikipedia's description, not ours.
The history
Cuttlefish ink as a writing fluid is classical, the Greeks and Romans used it. As a drawing medium it belongs to the late eighteenth and nineteenth centuries, where it did for wash drawing what bistre had done before and did it better, being warmer and more transparent.
The photographic connection is the part everyone half-knows and gets slightly wrong. Sepia toning of a silver print is a chemical process that converts metallic silver to silver sulfide, and the brown it produces is not cuttlefish ink. The name was borrowed because the result looked like a sepia wash. The reason it was done is that silver sulfide is considerably more stable than metallic silver, so a sepia-toned print lasts longer. Every brown Victorian photograph is brown because somebody was trying to make it survive.
Which means the 'sepia' filter on a phone is a simulation of a preservation technique, named after a cephalopod, standing in for the general idea of the past. There are three layers of borrowed meaning in it and none of them involve a cuttlefish.
Where it is used
Wash drawing, ink, watercolour, photographic toning, and now a shorthand for age in every visual medium there is.
It is the best example of a colour becoming a tense. Sepia does not mean brown, it means 'this is in the past', and that meaning is strong enough to override the content of an image. Worth knowing if you ever grade a photograph warm and wonder why it suddenly reads as nostalgic rather than as warm. You have not adjusted a colour, you have changed when the picture is.
Go and look at it
Nineteenth-century wash drawings
British Museum prints and drawings room, London
Warm, transparent, built in layers of wash. The medium is doing the modelling.
Any sepia-toned photograph
A family album
Brown because it was chemically converted to last. The look is a side effect of archiving.
How it behaves
- Made of
- Melanin from the ink sac of the cuttlefish, Sepia officinalis, treated with alkali.
- Opacity
- Transparent. It stains rather than covers, so it can be glazed over another colour.
- Lightfastness
- Moderate. It will move, noticeably, within decades, faster in thin films and tints.
- Fades in strong light as a watercolour, though better than bistre.
- Redissolves readily, which is excellent for washes and a nuisance for layering.
- Photographic sepia is silver sulfide and has nothing to do with the pigment.
The numbers
All derived from the hex, never typed beside it
- HEX
- #704214
- What a browser and a design file want.
- RGB
- 112, 66, 20
- The same three numbers in base ten. Light, not ink.
- HSL
- 30°, 70%, 26%
- Hue, saturation, lightness, how a person describes a colour.
- CMYK
- 0, 41, 82, 56
- Arithmetic only. A real separation depends on the press, the paper and a profile.
- LAB
- 33, 16, 35
- Perceptual. L* of 33 is how light this actually looks, which HSL gets wrong.
This hex is an approximation, and a page about pigment has to say so. Sepia 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 30°
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
8.47:1 · AAA
Handgloves
Black on it
2.48:1 · Fails
Handgloves
It on paper
8.04:1 · AAA
Handgloves
It on ink
2.16:1 · Fails
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
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