A 21st Century Indian Yellow!
An interesting but disturbing fact; Indian yellow used to be made by force feeding cows mango leaves and then collecting and concentrating their urine to make pigment. There are certainly many bad things to say about the modern chemical industries but thank goodness we no longer do that to cows. Quite frankly I am sure the diarylides are more lightfast, richer and have greater tinting power than cow urine.
The diarylide pigments were originally developed for the printing industry being very high chroma and extremely lightfast, these features alone are going to make good oil paint. However when the oil paint is produced by hand with no fillers and a very high pigment load you are going to get exceptional oil paint like this.
Langridge is pushing the boundaries of pigment use in paint making and I feel a true alternative to Cadmium Yellow cannot be far away...apart from its transparency this is pretty close.
Pigment PY14 - Disazo
Vehicle - Linseed Oil, Consistency - Stiff