- pigment names and numbers
- manufacturer’s name of the paint
- transparency or opacity
- price group or series
- ASTM conformance
- manufacturers name and address
- health warnings
There are variations with each company in the labeling of artist paints.
The lightfastness rating printed on a paint tube indicates the resistance of a color change when it is exposed to light. Colors can change in other ways besides fading, such as darkening, fading, lightening or turn grayer.
In the US the system for rating lightfastness is the ASTM, the American Standard Test Measure. Ratings are given from I to V. I is excellent lightfastness, II very good, III fair or non-permanent. IV and V are rated poor and very poor and are not used in artist paints. Thus, I, II, and III are all you need to be concerned with.
The system or scale used for rating the lightfastness of a paint and printed on the label depends on where it was manufactured. Two widely used systems are the ASTM and Blue Wool systems.
Pigment Names and Numbers
Every pigment has a unique code of two letters and some numbers. The two letters come first, they indicate the color family (PR = red, which stands for pigment red, PY = yellow, PB = blue, PG = green.) These letters and the following numbers identify a specific pigment. PY3 is Arylide Yellow or a common manufacturer name of hansa yellow. The color PR254 and PR209, has two different pigments mixed together. This may not be a color that mixes well with others.
You will probably not need to know the number of each color, but the use you may have for this is comparison. You can compare different manufacturers to see if they are made from the same pigment or not. If you see another number after the code, such as PY3 (11770), it is just another way of identifying the pigment, its Color Index Number.
Manufacturers Name of a Color
Paint names can be different with manufacturers. To compare colors in different companies check the pigment names and numbers, not the name of the color that they assign to each tube.
Transparency or Opacity
Not every company labels paints if they are transparent, opaque or semi-transparent. And, they can vary with the same paint color from company to company. The best way to really know is to physically compare them.
Paint Group or Series
This will tell you how expensive the paint is. They can be labeled either by number or letter. The higher the number or the letter, the more expensive the paint is.
ASTM Conformance Tests
ASTM is an organization which sets worldwide standards for a variety of products. It is voluntary compliance, so some paint companies do not use their standards.
Health Warning Labels
Health warnings vary by country. In the United States, requirements can vary by state. An ACMI Approved Product Seal on a paint label certifies that the paint is non-toxic to both children and adults, which means that it “contain no materials in sufficient quantities to be toxic or injurious to humans, including children, or to cause acute or chronic health problems”. ACMI, the Art & Creative Materials Institute, Inc., is an American non-profit association of art and craft supplies.