For the moment, let's assume we're hoping to create a convincing illusion of space and light in our paintings. This won't always be the case, of course, but a more symbolic interpretation of a scene demands a different kind of treatment (another homework assignment, perhaps).
On the blog we'll have to make do with a photo as our example. There is a big difference between working from life and from a photo. In some ways, I find plein air work easier, since the impossibility of including everything provides permission to summarize the scene rather than duplicate it. I also like being able to shift what is in focus, leaving other parts of the scene out of focus. Photographs don't give us that option.
Let's consider this image :
To see an illusion of space in a painting it is important to know where the major shapes are relative to each other. First of all, how many shapes do you see? If your number is greater than 12, consider simplifying by reducing the number. Can any adjacent shapes be combined without flattening the space too much?
In this scene composition is doing most of the work of revealing which shapes are in front of which. The overlaps are almost all quite clear. The most distant shape is an exception. It and the one just in front of it line up along their ridges so that their separateness vanishes when you squint. Why not make it easy for the viewer to read the space by adjusting the line.
There is a grand irony involved in attempting to create an illusion of depth. To perceive the space in a plein air scene we have to flatten it out, visually. A photograph has largely taken care of that already. Fortunately, the flatness of a photo can be approximated simply by closing one eye. Try it where you're sitting now. See how everything gets squashed onto a single plane? Overlap instantly becomes the main tool for understanding what is in front and what is in back. What happens at the edges where shapes meet or cross is all you've got to work with. How are the adjacent shapes different from one another?
Look for another place where the space is ambiguous. There's one all the way over on the left, where a group of bushes sit on the bank in the foreground. That shape is so similar in color and value to the hill behind it that the two merge. What might you adjust to make the separation of the shapes more apparent?
Working in plein air, it is easier to observe the spatial relationships of the shapes if you are not distracted by texture. Squinting gets the subtle details to smooth out, giving the shapes a more homogenous appearance. Squinting also allows you to see the value relationships the shapes have - the dark/light/middle pattern. This is the territory where the illusion of light resides. The structure these relationships create is much more important to the success of a painting than any amount of texture or detail.
If you have been finding plein air work intimidating, devote some time to letting go of texture and letting the shapes be in charge. Put aside any concerns you may have about your paintings being too simple without detail. In fact, for a little while, put aside the whole idea of producing paintings. Make some deliberately over-simplified studies, instead. This is important! Beginners, we'll go back to the warm/cool work in class next week.
For homework, distill the information in a scene down to a few shapes. Outline the shapes with pencil, and make any adjustments needed to their placement.
Assign each shape a value and a color, again, making any adjustments you feel will enhance the image.
OK, paint. Paint a lot. Let some of your studies be flat, hard-edged mosaics. Let some others be more fluid, allowing wet edges to intersect. See what happens when a shape changes color from one side to the other, but keep it simple. Avoid texture. Paint the tree rather than the leaves. Paint the forest rather than the trees. Paint the shape rather than the forest.