Introduction to Pigments and Powders
Pigments are composed of fine coloured particles that can be mixed with a binder to make paints. Common binders in artists' paints are linseed oil, gum arabic, and acrylic polymer.
Dyes are soluble and dissolve in the binding medium. This enables them to chemically bind with a material, which is why dyes are ideal for colouring textiles. Pigments are insoluble and are suspended within the binding medium.
The manufacture of artist paints consumes a tiny fraction of the pigment industry. The vast majority of pigments are used in larger industries, like in the production of cars and plastics.
Pigments are used to make artists' paints including acrylic colour, oil colour, watercolour, gouache, egg tempera, as well as oil bars and pastels. With pure dry pigment, you can create your own paints and pastels in the shades and quantities you like to paint with. Making your own paints can be a cost-effective means of acquiring paints that exactly match the way that you work.
What is the Colour Index™?
Created in 1924, the Colour Index™ is a database of pigments and dyes. It is published by SDC Enterprises and the American Association of Textile Chemists and Colorists.
Colourants are given many different proprietary and generic names. The Colour Index provides a standardised system used by manufacturers and consumers all over the world that can be a hugely informative tool for artists.
How Does the Colour Index Work?
Unlike other colour systems, such as Pantone or the Munsell System, the Colour Index groups dyes and pigments according to their chemical composition rather than the exact hue, value, and chroma of the colour they produce.
Each pigment entry has two identifying codes: the Colour Index Constitution Number, and the Colour Index Generic Name Code. For example, Ultramarine Blue is categorised under CI 77007 (the Colour Index Constitution Number) and PB 29 (the Colour Index Generic Name Code). The Colour Index Generic Name Code is most recognisable to artists. It’s common to find one or more of these codes listed on the tube or bottle of paint:
The letters classify the colour group. For example, PB = Pigment Blue, PW = Pigment White, PV = Pigment Violet, etc.
The number classifies the chemical composition. PB 29 can be read as ‘Pigment Blue 29’. This identifies it as sodium-aluminium-sulpho-silicate, or Ultramarine Blue. The number is not related directly to any part of the actual chemical structure. Rather, they are assigned chronologically in order of when the pigment was added to the index (not when the pigment was discovered).
Paintmakers are not obliged to disclose what pigments are in their paints. Some pigment mixtures, such as Winsor & Newton’s Cadmium-free colours, are proprietary and the Colour Index Codes aren’t given. Most paint ranges, particularly professional ones, do include them on the label.
Why is the Colour Index Useful for Artists?
Here are some of the reasons why it can be so useful to become familiar with the Colour Index:
1. The Colour Index provides insight into how different paints behave.
All pigments have individual characteristics such as transparency/opacity, tinting strength, granulation (in watercolour), drying rate, lightfastness, and permanence. All of these have a big impact on your painting. These pigment properties are determined by their physical attributes and chemical structure. While the exact science behind this is complex, knowing how certain pigments behave is a great way to get the most from your paints.
2. Colour names are not always reliable.
You can’t always rely on the name of the colour. As an example, here are the pigments used in a selection of paints labelled ‘Naples Yellow’. This is a historical toxic pigment that is often recreated for the modern artist using a mixture of pigments. Similar to food ingredient labels, pigments are usually listed in order of predominance (the pigment used in the greatest amount first, followed in descending order by those in smaller amounts).
- PW 6 (Titanium White), PY 42 (Synthetic Yellow Iron Oxide) – Old Holland New Masters Acrylic Paint
- PW 4 (Zinc White), PW 6 (Titanium White), PY 35 (Cadmium Yellow) – Sennelier Watercolour Paint
- PW 4 (Zinc White), PY 35 (Cadmium Yellow), PR 101 (Synthetic Red Iron Oxide) – Daniel Smith Watercolour Paint
- Pbr 24 (Chrome Antimony Titanate) – Michael Harding Oil Paint
- PBr 24 (Chrome Antimony Titanate), Pbk 7 (Natural Brown Iron Oxide), PW 4 (Zinc White) – Golden QoR Watercolour Paint
- PW 6 (Titanium White), PBr 24 (Chrome Antimony Titanate) – Winsor & Newton Watercolour Paint
It is worth noting that these pigment combinations make a great guide to mixing your own ‘Naples Yellow’.
3. The same pigment can have different names.
There can be huge variations in colour names among paintmakers – even for the most commonly used colours. For example, the blue pigment Copper Phthalocyanine was first sold under the trade name 'Monastral Blue'. It is now known by many other names and spelling variations, such as Monestial Blue, Helio Blue, Phthalo Blue, Thalo Blue, Winsor Blue, and Scheveningen Blue. The Colour Index classifies Copper Phthalocyanine as Pigment Blue 15 (PB 15). Seeing this on the side of a paint tube, you can quite reliably predict that the paint is transparent, deep in mass tone, and very strong in mixtures – traits that are typical in Phthalo pigments.
4. You can identify genuine pigments.
Genuine pigments are those which have some historical significance or particular characteristics but are sometimes recreated using mixtures of other pigments. Viridian Green (PG 18), for example, was used by the Impressionists, but is sometimes recreated with Phthalocyanine Green pigment (PG 7). Another example is genuine Van Dyke Brown (PBr 8), a historical deep brown made from iron oxide, clay, and bitumen, which is usually mimicked with a mixture of pigments. It’s important to note here that it’s easy to attach a certain romance to historical pigments, but they aren’t always the best. There are many toxic or non-lightfast pigments that have now been replaced with safer and more permanent modern pigments.
5. The Colour Index tells you how many pigments are in the paint.
The number of pigments in a paint matters to many artists. Single pigment colours – paints that contain only one pigment – are generally considered to be best in mixtures. This is because the more different pigments are mixed together, the muddier the resulting colour. If single pigment colours are important to you, then the Colour Index is invaluable to make sure you are using a single-pigment version of a colour.
Why Do Different Colours Have the Same Colour Index Code?
All pigments vary in hue, chroma, and handling characteristics. This depends on the way they are manufactured and processed. But, some entries in the Colour Index are more precise than others. Paints made using single pigment PY 3 (a pigment commonly known as Hansa Yellow Light), are almost always a bright, semi-transparent, lemon yellow. However, some Colour Index Codes cover a wide range of colours with very different characteristics.
A good example of this is PBr 7 (Pigment Brown 7). It refers to a Natural Brown Iron Oxide. Due to the natural variations of iron oxides, paints labelled PBr 7 can vary from yellowish-brown to dull red. Pigment manufacturers can control these variations. Burnt Sienna is produced by heating Raw Sienna, which partially dehydrates the iron oxide, making it darker and redder. The same goes for Raw Umber and Burnt Umber, two other Brown Iron Oxide pigments. So, Raw Sienna, Burnt Sienna, Raw Umber, and Burnt Umber can be categorised under PBr 7, even though they are very different colours.
Artists instinctively build knowledge about the properties of colour as they work. By familiarising yourself with the Colour Index, you can identify which pigments are best for you.
- White Pigments (Codes beginning PW)
- Yellow Pigments (codes beginning PY)
- Orange Pigments (Codes beginning PO)
- Red Pigments (Codes beginning PR)
- Violet Pigments (Codes beginning PV)
- Blue Pigments (Codes beginning PB)
- Green Pigments (Codes beginning PG)
- Brown Pigments (Code beginning PBr or NBr)
- Black Pigments (Code beginning PBk)
Dry Artist Pigments
Jackson’s Artist Pigment
Jackson’s range of Artist Pigments consists of 100 colours, all of which are suitable for making handmade paints. This includes egg tempera, oil paints, watercolours, or pastels. 10g is enough to make around 1-2 full pans of watercolour (depending on the pigment), so it is an ideal size if you are trying out a new colour. For larger volumes of paint, they are also available in pots of 100g.
Making Paint with Dry Pigment
When mixing water-based colours (watercolour, gouache, and tempera) use a hygroscopic product such as glycerin. This slows their drying time and makes them more flexible. The natural binder, either an animal or vegetable base, requires a preservative agent in order to preserve the integrity of the paints.
For oil colours, the most common binders are refined linseed oil or safflower oil. For whites and very pale blues, safflower or poppy seed oil is recommended as they are less likely to yellow with age.
When grinding your own paints, use a glass muller on a sheet of glass or polished marble. The longer you grind paint the more fluid it becomes, so be careful not to add too much oil. Each pure pigment has a particular chemical nature and therefore requires specific treatment.
Wet Bronze Powder
Brilliant bronzes moistened with solvent for oil paintings and bronzing. Add 3 parts Schmincke wet bronze powder and 2 parts bronze medium, such as Ormoline Bronzing Medium. To maintain gloss and luminosity, mix into a paste right before painting. The increase of binder results in better resistance to wiping.
Holbein Pigment Paste
Holbein Pigment Paste contains finely ground pigments suspended in a base of water, a wetting agent, and a dispersing agent. These colours have been developed as a base colourant with which to produce your own paint. There are no binders, fillers, or other chemicals added. They can be used as they are for block printing and monoprinting, and can be combined with a watersoluble binder, such as gum arabic or acrylic emulsion, to produce paint.
Frequently Asked Questions
Paints & Pigments: Popular Questions from Artists
Understanding Lightfastness
Lightfast means colours that do not fade when exposed to light, especially sunlight (UV radiation). Normal conditions are considered to be the most likely conditions where someone might display an artwork. For example, hanging on a wall indoors, out of direct sunlight, and framed behind UV protective glass.
Outdoor mural artwork can be protected with UV-resistant varnish.
To learn more, read ’Fugitive Pigments: Why Do They Fade, and Does it Matter?’ on Jackson's Art Blog.
Permanence vs. Lightfastness
Lightfastness is a pigment or dye's resistance to change because of exposure to sunlight and atmospheric conditions. Lower resistance means it could change hue or fade over time.
The permanence rating of paint includes its lightfastness, but adds the additional consideration of the durability of the binder. In modern times, top paintmakers will only ever use durable binders, so it is highly unlikely that anyone will experience problems. As a result, permanence is now less often used in this context.
When 'permanent' is used in the name of a colour, such as 'Permanent Alizarin Crimson', it refers to lightfastness. This is usually because the colour will be a modern replacement for a historic non-lightfast colour. The two terms are often used interchangeably.
An Explanation of the Difference Between Whites
The main types of white in artist colours all have different pigments. Zinc White is brittle, opaque and neutral in tint. Titanium White is opaque but can be prone to yellowing. Mixing White is usually a mix between Titanium White and another pigment. It is typically more translucent and less yellowing.
Read ’Pigment Colour Index: White Pigments’ on Jackson’s Art Blog to learn more.
Ultramarine Blue vs. French Ultramarine
‘Ultramarine’ – from the Latin ultra (beyond) and mare (sea) – originally referred to genuine Lapis Lazuli, a very expensive blue mineral pigment mined in Afghanistan. 'French Ultramarine' was used to describe the synthetic version, which was developed for commercial use.
Over time, synthetic ultramarine superseded Lapis Lazuli in availability and price. Manufacturers gradually dropped the word 'French' from the name. However, brands like Daniel Smith and Winsor & Newton still offer both Ultramarine Blue and French Ultramarine in their watercolour ranges – they are both PB29.
So what’s the difference? The difference may seem slight, but it's important for watercolourists. The particles in French Ultramarine are much bigger. This means that it granulates more in watercolour than Ultramarine Blue. French Ultramarine is slightly warmer (redder), whereas Ultramarine Blue is a little cooler (greener).
To confuse things some more, Schmincke also makes an 'Ultramarine Finest' watercolour. As the name suggests, this is very finely ground, which results in a less transparent and less granulating Ultramarine Blue.
Which Blue for a Zorn Palette?
Cobalt Blue or Ultramarine Blue would be suitable to use with the colours in the Zorn palette. The theory behind the Zorn palette – named after Swedish painter Anders Zorn – is that Ivory Black is used instead of blue to darken values. However, Anders Zorn did not always use the limited palette he is famous for, and was known to have also used Cobalt Blue. Ultramarine Blue is particularly versatile in mixes, and it is an excellent choice of blue if you are painting with a limited palette.
To learn more, read ’Colour Mixing: Exploring the Zorn Palette’ on Jackson's Art Blog.
Further Reading
Read our Pigment Stories series to learn about the most widely used pigments.
Fugitive Pigments: Why Do They Fade, and Does it Matter?
Making Handmade Watercolours with Dry Pigment
Making Your Own Oil Paint with Jackson’s Pigments
Interview with David Coles Langridge Founder
Ieva Kampe-Krumholca: Natural Pigments
Glossary
A
Alumina Hydrate
A fine white powder used as a filler and extender in paints and grounds.
Aniline Dyes
Synthetic dyes known for their intense colour. They often have poor lightfastness.
B
Binder
The substance that holds pigment particles together. Helps the paint adhere to a surface.
Bronzing Medium
A medium used to mix with metallic powders to create bronzing effects.
Burnishing
A technique of polishing a surface to enhance sheen or metallic effects.
C
Cadmium-Free Colours
Paints that have been made to mimic cadmium-based colours. They are a popular non-toxic alternative for artists.
Calcium Carbonate
Also called whiting. Used in primers and gesso to create texture and opacity.
Chromaticity
The purity and intensity of a colour. Not related to brightness.
Coagulation
The process where pigment particles clump together. This affects the consistency of the paint.
Colour Index
A system for identifying pigments and dyes based on their chemical composition.
Colour Shift
The change in colour appearance when wet paint dries.
Copper Phthalocyanine
A synthetic blue or green pigment with high lightfastness (PB 15, PG 7).
D
Dispersing Agent
A substance used to keep pigment particles evenly distributed in a medium.
Dry Pigment
Solid particles used to make custom paint formulations.
Dye
A colourant that dissolves in a medium. As opposed to pigments, which are insoluble.
E
Earth Pigments
Naturally occurring pigments such as ochres, siennas, and umbers, derived from iron oxide minerals.
Extender Pigments
Inert substances added to paints. Modifies texture, opacity, or drying time. Also see ‘Filler’.
F
Filler
An inert material used to bulk out a pigment. Often affects texture and opacity.
Fugitive Pigment
A pigment that fades or changes colour over time when exposed to light.
G
Gesso
A white preparatory primer made of chalk and binder. Used to prime surfaces for painting.
Granulation
A characteristic of certain pigments where the particles settle unevenly on a surface.
Gum Arabic
A natural binder used in paints to hold pigment in suspension.
H
Hue
A replica of a colour. Artists use hue colours for various reasons. Hue colours are often more affordable, as some pigments are rare and therefore very expensive. Some hue colours are created to be safer or more lightfast versions of historic pigments. This is because some historic paints were toxic or fugitive.
I
Inert Pigment
A pigment that does not chemically react with the binding medium or other pigments.
Iron Oxide
A common category of earth pigments. This includes red, yellow, and brown iron oxides.
Isopropyl Alcohol
A solvent sometimes used to disperse pigments in acrylic paints.
L
Lake Pigment
A dye combined with an inert base. Often used in watercolours and pastels.
Lightfastness
The resistance of a pigment to fading when exposed to light.
Luminous Pigment
A pigment that emits or reflects light. Often used in fluorescent or phosphorescent colours.
M
Metallic Powder
Finely ground metal used to create metallic effects in paints.
Muller
A tool made of glass or stone. Used to grind pigment with a binding medium.
Munsell System
A colour classification system based on hue, value, and chroma.
N
Natural Pigments
Pigments derived from minerals, plants, or other organic sources.
Non-Toxic Pigments
Pigments formulated to be safe for human use. Made to replace historic toxic pigments.
O
Opacity
The degree to which a paint covers the surface beneath it.
Ochre
A naturally occurring yellow to brown pigment. Derived from iron oxide.
Oil Absorption
The amount of oil required to bind a pigment into paint.
P
Particle Size
The fineness or coarseness of a pigment. Affects texture and dispersion.
Precipitated Pigment
A pigment formed by chemical reaction. Often used in synthetic colour production.
R
Raw Sienna
A natural earth pigment classified under PBr 7. Contains hydrated iron oxide.
Red Oxide
A synthetic or natural red iron oxide pigment with high lightfastness.
S
Safflower Oil
A non-yellowing oil binder. Used in pale oil paints.
Saturation
The intensity or purity of a colour.
Shade
A colour variation created by adding black or a darker hue.
Silica
A mineral used as an extender in paint formulations.
Staining Pigment
A pigment that strongly adheres to a surface and is difficult to lift (e.g., Phthalo Blue).
Synthetic Pigments
Man-made pigments. Often more consistent and stable than natural alternatives.
T
Tinting Strength
The ability of a pigment to influence a mixture.
Transparent Pigment
A pigment that allows light to pass through. Often used for glazing.
U
Umber
A natural brown earth pigment. Available in raw and burnt forms.
V
Vehicle
The liquid in which pigment is dispersed. For example, oil, water, or acrylic.
W
Whiting
Another term for calcium carbonate. Used in grounds and primers.
Wet Bronze Powder
A metallic pigment moistened with solvent. For painting and bronzing.