Understanding Watercolour Pigment Codes
Why are pigment codes important?
Iris watercolour painting with 2 of the colours used
Watercolour paint primarily consists of pigment blended with gum arabic, glycerin, and a wetting agent to enhance its handling properties. As an artist, you know that identifying the ingredients used in your paint is crucial to achieving the exact colour shades you need. However, deciphering the technical names of pigments can be a headache.
The Colour Index International
The Colour Index International is recognised internationally as a standard for colour naming and numbering.
The pigment code is composed of both letters and numbers that indicate the colour and type of pigment used. The letter indicates the family that the pigment belongs to, while the number indicates which particular colour it is from that family.
These simple codes are actually easy to understand. Each code begins with the letter P for pigment, followed by a letter representing a basic colour category. For instance:
Y = yellow,
O = orange
R = red
V = violet
B = blue
G = green
Br = brown
Bk = black
W = white
For example, the pigment code "PY-53" stands for "Pigment Yellow 53".
The number 53 indicates that it is the 53rd yellow pigment listed in the Colour Index International.
Using blue paint from my palette
Why is it useful for artists to know the pigment codes of paint?
Knowing these pigment codes can help you identify specific colours and their properties, including lightfastness, opacity, granulation and staining qualities. This information can be invaluable when selecting watercolour paints to create your artwork. It also enables you to mix colours accurately and hopefully achieve the desired results every time.
Selecting watercolour paints
It’s useful to know the pigment codes of the paint you use because colour names vary between different brands. The same pigment can have different names. For example, the pigment code PB15 is called Manganese Blue Hue in the Daniel Smith brand but it’s called Winsor Blue (red shade and green shade) in the Winsor & Newton brand.
If you are following a painting tutorial, knowing the pigment codes can help you substitute colours between different brands. 🤗
However, not all brands of paint use the same pigment codes and some brands may use blends of pigments. The quality of the pigment can also vary between brands so make sure you experiment with different paints to find the best option for your needs.
Knowing the pigment code helps you mix colours
Some paint colours are made up of more than one pigment which is something to keep in mind when working with watercolours. It’s best to avoid using too many pigments when mixing watercolours. Watercolour paints are known for their freshness and transparency, and using too many pigments can increase the likelihood of creating muddy or dull colours.
A tube of French Ultramarine watercolour paint, pigment code PB29
Where do you find the pigment code?
You can usually find the pigment codes of watercolour paints on the packaging or label of the paint tube or pan.
If you're unsure about the pigment codes of a particular brand of watercolour paint, you can try looking it up online or contacting the manufacturer for more information. Some manufacturers also provide detailed colour charts that list the pigment codes for each colour in their range.