"One of the joys of the quinacridone reds is that they come in such a variety of shades. This is because they are so useful in many industries such as cosmetics and plastics but especially for automotive coatings. No other class of pigment provides so many varieties that are attractive pinkish and blue-red through to magenta and violet colours and is highly lightfast at the same time. Because cars tend to last for less than 20 years we tend not to think about the paints in terms of permanence but for a colour to be outdoors in full sunlight and a wide range of harsh weather conditions is the greatest test a colour is normally subjected to. 500 years on a gallery wall for an artwork is like a walk in the park by comparison. So any colour that proves itself in the automotive paint industry is going to be perfect for artists use. Of great benefit to artists is the fact that huge sums of money are spent on colour research for automobiles and manufacturers want as many pretty shades as possible.
Artists paints suffered for thousands of years because of the fugitive nature of most red colours available in earlier years. Or they were highly poisonous. We are very fortunate to live in an age when we have the quinacridones. Not only are they non-toxic, they are highly permanent (comparable to the Cadmium Red in that regard) and provide the much needed blue-reds that the pyrroles cannot provide. This particular shade is one of the first red variants developed from what was originally a more violet quinacridone (no, Matisse did not make a mistake when they list the pigment information as PV19) and is particularly transparent. if opacity is required then reach for the Cadmium Red but transparency is required. The artist may be using a glazing technique, or looking for that jewel-like fire in a colour from the light traveling through the colour. If that is what is needed then put the Cadmium Red back and reach for the tube of Quinacridone Red.