In this post I'm going to cover:
• (Very!) basic color theory
• Some general tips to bear in mind while you're translating "what you see" into oil paint
• How I think through a paint mix
This goes hand-in-hand with "Part 1", which is about the various physical qualities of the specific oil paints I use, plus some notes on how they interact in real color mixes. Find it here: http://www.conceptart.org/forums/sho...d.php?t=170685
Basic Color Theory: ROYGBIV is the spectrum (red, orange, yellow, green, blue, indigo, and violet). In painting, we are dealing with subtractive light (a color absorbs absent/lesser hues while reflecting dominant ones). It's important to note (for all ye raised on Photoshop ) that this is different from the Emissive light we get from monitors. It's also different from printing (CMYK; cyan, magenta, yellow, black).
The Primary Colors are: red, yellow, and blue. Mix any two together to get Secondary Colors (green, orange, and violet). Mix any two of those to get the Tertiary Colors (blue-green, red-violet, yellow-green, etc). Complementary Colors are colors that are opposite each other on the Wheel. (See the diagram below.)
Value refers to how light or dark a color is. Saturation is how pure/intense a color is. Anytime you mix another paint into a raw oil color you are somehow diluting this Saturation Purity.
Mixing/Seeing/Translational Tips: You're going to hear this next thing from me a LOT in this series. If there is one "secret" to Painting--one thing that'll make your artistic life fruitful, worthwhile, and considerably easier (a Lie, but you get the idea!)--here it is: Whether you're working Naturalistically, from life, or inventing a painting...think about "Little Pieces of Light and Color" (hat tip to my greatest painting instructor ever, the mighty Mark Karnes). It's very simple, but maybe it sounds cryptic to you.
Here's the breakdown: All perceived color is relational ("color", here--defined in a general sense--refers to all aspects [hue, sat, value, and relative temperature] of a defined, quantum patch of perceived light). When you're painting you look at your scene, and pick a place to start. You carefully mix a color that corresponds to what you see for that patch. Now the "secret"--the Heavy Artillery of Painting! Ready to get bowled over? Are you prepared to take in the same idea that made me understand how to construct a painting after a lot of hit-and-miss flailing? Good!
You look right next to the patch in your scene from which you made your first decision, and determine: its color, whether it's lighter or darker than that patch, and whether it's warmer or cooler than that patch. Mix that color decision up on your palette, and lay it in right next to the last patch. Keep working "What goes next to the previous patch" like this til your painting is done. If you do this diligently, you will be amazed (reasonably frequently--since nothing's really a silver bullet) at how your paintings start to truly reflect your visual experience--and that's what good paintings do. Even if you're working out of your head, as we all do sometimes, asking those three questions lead you to more deliberate and interesting decision-making.
You may have noticed that this completely tips the Sacred Cow of conventional wisdom about "working a painting All Over, general to specific". Once you see the power of this technique (most especially for painting from life), you'll see how All-Overness can be a recipe for over-generalized or procrastinatory decision-making that ends up showing less interesting painting. I'll go into all of this in greater detail when we get to actual painting, but it's important to bring it up in a mixing talk.
Other tips: Push the temperature aspect. If something looks darker (but warmer) than what's next to it, make sure to push, just a bit, that color/temperature difference--as well as the value. Stone-cold grays also become very beautiful resting places for the eye when you do this, when done judiciously.
About White: white is necessary in painting, obviously, but if you add too much it kills the intensity and color. Think of new ways (still using the "what goes next to what" advice) to make a patch "approach" or "jump"-other than using white. Since color is relational, keep in mind that juxtaposing complementary colors creates Vibrating Boundaries that can be used to excite the eye without whiting something out. Value, of course, can do this as well.
About Black: We're not going to use it. When dealing with the warm/cool thing, there are lots of ways to create super-dark values without black. See that Part 1 post for paint mixtures that can do this.
Intensity: You can use this to mimic optical phenomena. Let's say you're doing a landscape painting and there's a bank of trees with sky over it--and peking through it. You've used Ultramarine blue and white for the major sky pieces directly over the trees. Where the sky peeks through the trees, however, you want to *up* the saturation a bit by backing off the white.
There's prolly more I should say, but I'll add it in an Addendum to this post if I think of anything. I know there's a lot of info here, but take it in pieces, take your time, and...experiment!
You'll get it, you will.