Brain Pickings has a great bit of coverage highlighting this phenomenal work from German poet and philosopher, Johann Wolfgang von Goethe: Theory of Colours.

Leave it to an artist and poet to contend the prevailing thoughts on light and color (Newtonian at the time) with a potent mix of what would now be seen as cognitive psychology, perceptual reasoning and poetry. ​

It is his descriptions of the psychological impact of color that is most arresting. Here are just a few samples. And a link to greater details on Brain Pickings.​