From Michael Harding:
Organic Pigment – Green Gold is a pigment I have admired for many years, although essentially a modern colour. As a standalone pigment, it brings to your painting a unique green that has its own elegance. However, when mixed it is “weird!”
When you first look at it as a single colour it is very interesting , however, when mixed with other transparent colours like Alizarin Claret or Magenta it does extraordinary things. One wonders where the “third” colour came from as it seems quite magical. The magical qualities of Green Gold give it a high tint power and high capacity for being lightfast. Remember, because Green Gold is a transparent colour it has wonderful glazing properties and power.
There is only one organic pigment in my Green Gold and as such this pigment is highly transparent and lightfast.