If you're interest in the history of color theory ...

[kenny]

I love science, history and color, so I found this fascinating.

Published in 1766, The Natural System of Colours by Moses Harris, is a significant work in the history of color theory.



Enjoy

The Natural System of Colours

Recreating Moses Harris’ color wheels from the eighteenth century.

www.c82.net

 

[Autumn in New England]

I've been obsessed with this since I was a child, and I firmly believe my love for gems is a direct extension. Great article, thanks!

 

[Starstruck8]

Thank you for this, @kenny. Fascinating, as you say. At the end of the article is a link to Rougeux's blog. This gives even more details.

Here is a link to a transcription of Harris' booklet (a pdf, a bit easier to read than the Library of Congress page images Rougeux links to):
https://colorysemiotica.wordpress.com/wp-content/uploads/2015/04/harris1770.pdf

Having read Harris's booklet, I think Rougeux's project was misguided. Rougeux tried to reproduce Harris's colour wheels by (digitally simulated) mixing of three 'primary' paints. But as I read Harris, his wheels were intended as a conceptual arrangement of colours. They were not intended to accurately represent the effect of physical mixing of paints. Harris says of his wheels: With respect to the colouring of both parts of the system it is intended but to elucidate, direct the eye, and assist the ideas of the reader, and it must be observed here, that the author treats on colour in the abstract. Colour which we may call material, or artificial, are very imperfect in themselves... (My emphasis.) My guess (maybe wrong) is that Harris tried to make the colours in his 'prismatic' wheel as saturated as he could, using whatever pigments he had. That's why he called it prismatic.

In any case, Harris did not colour his wheels solely by mixing his red. yellow and blue primaries. You can see this in his 'prismatic' wheel:

(Left: Harris, 1st edition. Right: Rougeux.)

Harris's purple-red (to the left of red) really is purple-red, even on faded paper. It could not have been made by mixing (Haris's) red with ultramarine. Most likely, Harris used an actual purple-red pigment. Rougeux's purple-red is brown, just as expected from a mixture of Rougeux's red and ultramarine.

 

[stracci2000]

If you have red, blue and yellow, you can make most any color.
We studied this in art school. It's awesome, really.
Roy G. Biv (red, orange, yellow, green, blue, indigo, violet) also fascinates me.
And what about cyan, magenta, yellow and black.....
Pantone's color if the year is "mocha moose"
My favorite watercolor is Payne's Gray.
Cool stuff to learn about!

 

[kenny]

Starting with finger-painting in kindergarten we've all been taught that the 3 primaries are red blue and yellow, RBY.
... Simple, and nearly universally agreed upon.



But it's not quite true, rather it's not the full story.
It's complicated and not something 5 years olds, or many adults, will absorb.

RBY applies to pigments only.
The primaries for light are RBG, with green instead of yellow.
Why?
The answer requires learning about additive vs. subtractive color mixing and what happens in the human eye.

Here's a good primer:

Primary Colors Are Red, Yellow and Blue, Right? Not Exactly

Primary colors are the blocks from which all other colors are built. But there's a lot more to know about them than the basic red, yellow and blue we learned about in kindergarten.

science.howstuffworks.com

 

[Starstruck8]

Starting with finger-painting in kindergarten we've all been taught that the 3 primaries are red blue and yellow, RBY.
... Simple, and nearly universally agreed upon.

But it's not quite true, rather it's not the full story.
It's complicated and not something 5 years olds, or many adults, will absorb.

RBY applies to pigments only.
The primaries for light are RBG, with green instead of yellow.
Why?
The answer requires learning about additive vs. subtractive color mixing and what happens in the human eye.

Here's a good primer:

Primary Colors Are Red, Yellow and Blue, Right? Not Exactly

Primary colors are the blocks from which all other colors are built. But there's a lot more to know about them than the basic red, yellow and blue we learned about in kindergarten.

science.howstuffworks.com

Yes! And it's worse than that. No finite set of 'primaries' can be mixed to give all colours. CMYK for pigments and RBG for lights give a usefully wide range of colours at a reasonable cost. But they can't produce all colours. As the linked page says: ...the idea that three pure primaries can create all the colors in the world is totally false. "We cannot make all colours from three primaries, no matter how carefully we choose the primaries," he says. "We cannot do it with additive colour mixing, and we cannot do it with subtractive colour mixing. If we use three primaries, we can make all the hues, but we cannot make all the colours; we will always struggle to make really saturated (vivid) colours."

It took me a long time, with much reading and thinking, to sort this stuff out. Some of what you can read, from people who should know better, is plain wrong. The linked page is a good start, but only a start. I have found Bruce MacEvoy's 'Handprint' site useful.
On colour vision: https://www.handprint.com/LS/CVS/color.html
On colour theory: https://www.handprint.com/HP/WCL/color18a.html
These are extremely detailed and not light reading at first. But they are thorough, well referenced, and seem to be reliable. MacEvoy does a good job of debunking most of the misconceptions I've come across.

But here's something I still don't understand: 'unique hues'. Certain hues of red, green, yellow and blue are supposedly seen as pure, meaning that they are not seen as mixtures of other hues. Other hues are supposedly seen as mixtures. Thus, it seems natural to describe orange as a mix of red and yellow. But it would seem odd to describe red as a mix of purple and orange. So what makes red and yellow special compared with purple and orange? There are theories, but no consensus that I can see. That aside, which precise hues are the 'unique' ones? There was a thread called something like 'What is the true red?' Someone said that many people's idea of 'pure' red was actually a bit orange. So what is the 'true red'? Is there a physiologically/psychologically based 'true red', or is it just an arbitrary convention? The same applies even more to green. maybe not so much to blue and yellow.