A tube of artists’ colour holds a lot more information than just the colour name. Winsor & Newton colours always show the information artists have asked to see.
The diagram below explains what each label tells you about the colour inside:
Name of range: Identifies the colour range.
Colour name: The name of the colour. These are not necessarily unique to a range or medium. For instance, Cerulean Blue is available in watercolour and oil colour.
Series number: Indicates the relative price of the colour and is determined mainly by the cost of the pigment. Series 1 is the least expensive and Series 5 is the most expensive.
Colour swatch: Shows how the colour will look when painted out, so there’s no need to open the tube.
Quantity: Indicates how much paint is in the tube.
Permanence rating: The Winsor & Newton permanence classifications measure not only lightfastness but also film and chemical stability of the paint. The ratings are:
AA: Extremely Permanent
B: Moderately Durable
Pigment number: Each pigment can be identified by its Colour Index Generic Name. For example, Cobalt Blue is Pigment Blue 28, abbreviated to PB28. More than one pigment abbreviation indicates multiple pigments.
Opacity: Symbols are used to represent the transparency or opacity of a colour.
Lightfastness: Shown with an ASTM rating for the pigment. In this system, I is the highest lightfastness available and V is the lowest. Both ratings I and II are considered permanent for artists’ use. ASTM stands for the American Society for Testing and Materials, an organisation that has set standards for the performance of art materials, including a colour’s lightfastness.
AP Symbol: AP identifies art materials that are safe and that are certified in a toxicological evaluation by a board-certified toxicologist (medical expert) from Duke University to contain no materials in sufficient quantities to be toxic or injurious to humans, including children, or to cause acute or chronic health problems.