Color stories · 16 pigments

The watercolor pigment library

Every color on a paint rack has a story, and most of the stories are stranger than the color. This is where I keep them, one pigment per page: what the color is, where it came from, what is in the tube today, how to mix it, and where it does its best work.

A pigment is a colored powder that does not dissolve in water. It sits on the paper as tiny particles, which is why watercolor glows: light passes through the paint, bounces off the white paper, and comes back out through the color. A dye dissolves and stains the fiber instead. Some of the pigments below started life as dyes, or as rocks, or as the ink of a cuttlefish, and became paint by way of chemistry.

Each page carries the same facts in the same place, so you can compare two colors side by side. The Colour Index code (PB29, PBr7, PG7) tells you the actual pigment regardless of the name on the tube. Lightfastness tells you whether it will fade. Granulation and staining tell you how it behaves on wet paper. If a name is a mixture rather than a single pigment, the page says so, because that is the thing most labels leave out.

Blues

Indigo Indigo color is the deep blue between blue and violet in the rainbow, named after the plant d... Prussian Blue Prussian blue is a very dark, green-leaning blue made from iron and cyanide, and the first pi... Ultramarine Blue Ultramarine is a deep, slightly violet blue, once ground from the stone lapis lazuli and sinc... Phthalo Blue Phthalo blue is a deep, intense, slightly greenish blue made from copper phthalocyanine, a sy... Cerulean Blue Cerulean blue is a light, slightly greenish sky blue made from cobalt and tin. It is the blue... Cobalt Blue Cobalt blue is a clear, true blue with no green or violet lean, made from cobalt and aluminum...

Greens

Viridian Viridian green is a cool, transparent blue-green made from hydrated chromium oxide (PG18). It... Phthalo Green Phthalo green is a deep, cool, blue-leaning green made from a chlorinated copper compound (PG... Emerald Green Emerald green is a bright, clean, slightly blue-leaning green named after the gemstone. The o...

Reds

Vermilion Vermilion is a warm, orange-leaning scarlet made for most of history from cinnabar, the ore o...

Earth colors

Sienna Sienna is a warm earth color named after the Tuscan city of Siena. Raw sienna is the yellow-b... Yellow Ochre Yellow ochre is a soft, earthy yellow made from iron-stained clay, one of the oldest pigments... Umber Umber is a natural brown earth colored by iron oxide and darkened by manganese. Raw umber is ... Burnt Sienna Burnt sienna is a warm, transparent red-brown made by roasting a natural iron earth. It is th...

Browns and darks

Sepia Sepia is a deep, warm, black-brown named after the cuttlefish whose ink it was once made from...

Grays and neutrals

Payne's Gray Payne's gray is a cool, dusty blue-gray that painters reach for instead of black. It is a mix...

How to read a pigment page

The facts table on every page uses the same six lines. Here is what they mean in plain words, and why I care about each one.

Colour Index	The pigment's real name, like PB29 for ultramarine or PBr7 for the sienna and umber earths. Two tubes with different marketing names and the same code are the same pigment.
Transparency	Whether light gets through to the paper. Transparent colors glaze and glow; opaque ones cover and go chalky when overworked.
Lightfastness	How well the color survives daylight. Excellent means your painting looks the same in fifty years. Fugitive means it will not.
Granulation	Whether the pigment settles into the texture of the paper and dries speckled. Ultramarine, cobalt and the earths do it; phthalo and quinacridone stay smooth.
Staining	How hard the color is to lift once it is down. Staining colors are unforgiving and brilliant in glazes; low-staining ones let you fix mistakes.
Toxicity	What was dangerous about the historical version and whether the modern tube is safe with normal handling. Nearly always yes. Do not lick the brush anyway.

The Tobio's Watercolor Kit has twelve colors, and none of the historical pigments in this library is among them, on purpose. A beginner's palette should mix, not collect. So every page ends with the closest mix from the kit, tested on scrap paper before I wrote it down, and the interactive color mixing chart lets you try any two of the twelve before you commit.

See the kit

Questions people ask about watercolor pigments

What is the difference between a pigment and a dye?

A pigment is a solid particle that does not dissolve; it sits on the paper held by the gum arabic binder. A dye dissolves and soaks into the fiber. Watercolor is made from pigments, which is why it can be lifted, layered and left to granulate.

What do codes like PB29 or PBr7 mean?

They are Colour Index generic names. P stands for pigment, the letters for the hue family (B blue, R red, Y yellow, G green, V violet, Br brown, Bk black, W white), and the number identifies the exact chemical. PB29 is always synthetic ultramarine, whatever the label calls it.

What does lightfastness mean in watercolor?

How much a color fades in light over time. Manufacturers rate it on scales such as ASTM I to V or the Blue Wool scale. For anything you want to keep or sell, stay with colors rated excellent or very good and treat the fugitive ones as sketchbook colors.

What is granulation?

Some pigments have heavier or coarser particles that settle into the dips of the paper as the wash dries, leaving a speckled, textured look. Ultramarine, cobalt blue, cerulean and most earth colors granulate. Fine synthetic organics like phthalo blue and quinacridone dry smooth.

Are watercolor pigments toxic?

Modern beginner ranges avoid heavy metals entirely. Cadmium and cobalt colors are still sold to artists and are safe with normal handling, since the risk is in breathing the dry powder, not in painting. The genuinely dangerous colors in this library, like emerald green and vermilion, are historical, and the tubes sold under those names today are recreations.

Why does the Tobio's kit have only twelve colors?

Because mixing teaches you more than owning. Twelve well-chosen colors reach almost every hue on these pages, and the act of mixing them is how you learn what warm, cool, transparent and granulating actually mean on paper. Each pigment page shows the closest mix from the kit.

Mel, founder of Tobio'sI make portable watercolor kits and I named the company after my cat. I write these pages for the beginner I used to be, one pigment at a time.