Aureolin or Cobalt Yellow (PY40)
The pigment was first produced by the German chemist Nikolaus Wolfgang Fischer in 1831, hence the name Fischers yellow. But later, when the pigment became a paint for artists’ colors, it was called aureolin. As early as 1861, it appeared as an artist’s color in the Winsor & Newton range. Aureolin was initially presented as a substitute for the organic pigments gamboge and Indian yellow.
Cobalt yellow has a big disadvantage, the pigment is not light-resistant, it’s a shame, otherwise the color would have been the perfect cold-yellow color. Aureolin is transparent, has fine blending properties and is much nicer than all modern primary yellow pigments, but it does not tolerate sunlight, unfortunately.
All the manufacturers who have real pigments say that their aureolin has good lightfastness, but the reality is different, all real aureolins turn gray-brown when exposed to sunlight. According to Bruce MacEvoy from handprint.com, the best are Rembrandt and Rowney (Rembrant has since the test changed from genuine to fake pigments) while Daniel Smith, Sennelier and Winsor & Newton are worse in terms of light resistance.
If you can stand the fact that the color will eventually turn brownish gray, you may make illustrations and not pictures that will hang on a wall, then you can use aureolin, it is a fantastic color. If, on the other hand, the thought that your beautiful yellow rapeseed fields will look withered after a few years bothers you, avoid the color.
There are not many manufacturers that use aureolin for the color they call aureolin. Most manufacturers use other yellows but still call the color aureolin. In other words, they are cheating. A few add the word “hue” which indicates that it is something other than the real pigment. But it’s a classic pigment, so everyone should have it, even if it’s just a fake. It is also an expensive pigment, which gives manufacturers additional motivation to use other cheaper pigments.
DANIEL SMITH: Aureolin PY40
DALER ROWNEY: Aureolin PY40
WINSOR & NEWTON: Aureolin PY40
SENNELIER: Aureolin PY40
SHINHAN: Aureolin – Pigment: Synthetic iron oxide PY42
ST PETERSBURG : WHITE NIGHTS: Aureolin – Pigment: benzimidazolone yellow PY151
MIJELLO: Aureolin Pigment: – arylide yellow PY3 benzimidazolone brown PBr25
HOLBEIN: Aureolin Pigment: – benzimidazolone yellow PY154 benzimidazolone yellow PY175 nickel azomethine yellow PY150
SCHMINCKE: Aureolin hue – Pigment: benzimidazolone yellow PY151
LUKAS: Aureolin – Pigment: benzimidazolone yellow PY175
HOLBEIN: Aureolin – Pigment: benzimidazolone yellow PY154 PY175 nickel azomethine yellow PY150
ROYAL TALENS: Aureolin – Pigment: nickel azomethine yellow PY150
ROMAN SZMAL: Aureolin (hue) – Pigment: benzimidazolone yellow PY15