– What happens when an artist mixes paint for a painting? Are the pigments actually changing physically/chemically? What is actually happening to make the paints change color?

Question

– What happens when an artist mixes paint for a painting? Are the pigments actually changing physically/chemically? What is actually happening to make the paints change color?

In: 4221

Answer 1

I also want to tell you about Streak.

If you take a chunk of a mineral or colourful rock (lets say it’s dark blue) and grind it up into a powder to mix with oil to form a paint, it’s possible that the ground up rock powder won’t also look dark blue. Maybe it now looks light blue.

So your dark blue rock only makes light blue paint.
It’s the size of the little rock particles, bouncing with the light, that ‘change’ the colour to our eyes.

Because of this, not all rocks/minerals are used to make paint. In the pre-industrial era (pre-1800s), there’s only something like 25 minerals commonly used to make paint in the Western part of the art world. There are also a few other things used to colour paint, like bugs or plant dye, but most paintings are made with crushed mineral/rock paint.

Source: I was a forensic art chemist.