I've been reading a lot about color harmonies and trying to learn "What all great artists know". But once again, after a period of focused research, the main thing I've come up with is that I don't agree completely, with anyone. I bought a couple of books because I found information and color schemes in them that I really like: Color Is Everything by Dan Bartges introduced me to the idea of a tetrad color scheme, which I had never heard of. I ordered a copy of Dan Quiller's Painter's Guide To Color so I could get a copy of his Quiller Wheel, which shows most of the manufactured water color pigments where they would actually show up on a color wheel. I have a few other older books that have really good information on color. The first one that really opened my eyes on color mixing was Jeanne Dobie's Making Color Sing. Another book from which I learned about the importance of greys from was Ted Goerschner's Oil Painting: The Workshop Experience. Even though he doesn't talk about color theory as such, I ended up studying his use of color, and of greys, a great deal because of how much his paintings appealed to me. The idea of mixing up greys ahead of time to use along with pure hues was revolutionary to me. Robert Burridge is another painter whose very original approach to color really made me stop and rethink my habitual approaches to color. He has invented his own, unique and non-standard color wheel, and uses it to make beautiful paintings that really don't look like anyone else's.
After spending a fair amount of time really reading and studying these books, I took out my standard color wheel and went through several online archives of my favorite world-famous artists and tried to analyze their paintings to see what were at least the 4 or 5 significant colors in each painting, and to figure out which, if any, color scheme they were following. What I found is that almost none of the paintings and artists I really like follow someone else's, or even the standard color harmonies. There are some works that have recognizable triads, or complements, or split complements, but the exceptions--even what I could find on the web--so outnumber them as to leave me with a strong conviction that I just need to make my own rules. Take my new painting:
I was so enamoured of a tetrad painting in Color Is Everything which used blue, orange, yellow-green and red-violet, that I wanted to try a similar one of red, green, yellow-orange and blue-violet. With just those four colors, though, even adding neutrals and sub-neutrals of them and providing enough dark and light values to give me the depth and contrast I wanted, I still wasn't happy with the results. Eventually I ended up adding blue for the sky and several yellow-green tones to the trees and other foliage. So technically, I end up with what amounts to a combination of the original tetrad plus an analogous scheme with holes in it. I'm willing to bet that no book or teacher you ever come across will propose that you use an "analogous scheme with holes in it".
But I think starting with the tetrad was a good idea, because I got the rich range of colors I was looking for. The red really wakes up the green, and the pale yellow orange of the clouds plays very well of the blue-violet of the shadows and distant hills. Visually, it feels like a full meal, and that's what I wanted.
I think that ultimately, my subject combined with the time of day dictated my color scheme. Perhaps with a more abstract subject, or a more controlled background like an interior, I can get satisfactory paintings that follow standard color schemes. I do plan to do a lot more experiments with color combinations I've never tried. If there's an ounce of nurd in you, I think you'll really enjoy conducting a color analysis of your favorite artists and paintings. And I think at this point that copying color schemes from other paintings you like is just as good a way to experiment as starting with a color wheel.
But, anything you can learn about color is useful. A couple years ago I was amazed to find I could make nice tree colors by mixing sap green and red-violet. Now it's really nice to be finding so many more colors I can use for shadows and highlights—blues, violets, reds, browns and golds. I want them all! I want all the colors!