The onion (Thinking in layers)
Before laying down a stroke, there's a number of things you need to think about. Well, actually you shouldn't have to think about them, it should just go automatically.
- Feel volume and angle of the form.
- Where is the light coming from?
- Try to figure out if there are any shadows that might be falling on the surface.
- Is there any reflected light (radiosity) that hits the surface?
- What is the ambient color of the scene? (sorta like global reflected light.)
- Any speculars. Is the surface gloss/wet and also angled so it reflects a light source, such as the sky?
- The exposure level. Perhaps it's so heavily lit that it becomes more than white? Perhaps it's so dark that even the brightest spot is hidden in darkness.
- Is there any fog in the way?
- The texture of the surface.
Note that this mainly goes for realistic styles. A brushstroke should also look efficient and consistent with the rest of the painting and your color scheme choice. You might also have an idea or style which disallows certain colors or textures and puts priority on other things. However, even in a powerpuff girls illustration there's simplified elements of realistic rendering. Don't hide behind "it's not apart of my style so I'm not gonna learn it".
Orders of importance
Very generally speaking, certain apects of a painting are more important than other.
- Construction - What are you trying to paint? Your subject and composition should work on a fundamental level. If not, then no rendering in the world can save it. Don't have any illusions that you will be able to salvage the piece later. If a pose look wrong now, it will look stiff when finished too, even if Rembrandt himself painted it.
- Values - For a painting to work you need to use values to sculpt the forms. Values can do a lot of work grouping and separating shapes. Example 1 - The first version here is obviously wrong. Each shape has just gotten the shadow and highlight treatment. Second one is better but there's just one value type. Third one has different values on different shapes. Maybe it fails at the construction step though; it's not a very interesting pinup. Example 2 Here both value and color is used to separate the foreground and background, although I don't like this painting either, again it fails at construction.
- Color - You can be a little off with the colors (hue and saturation) and still get away with it. If you just can't make the colors work, it is probably the values that are wrong. On a side note, if the previous steps do work, it's easy to make fresh looking images with color balance tools. In my experience the original choice is often the best.
This is taken from a tutorial by Arne Niklas Jansson - 2005 & 2007
I think it is quite useful when looking and telling you how to paint. Although digital painting isn't something new to me, I have often found myself always coming back to the same three tools. Sadly I know realise that i've been doing int wrong and this isn't the way about it if I am to get more realistic results.