Our aim for simplicity and clarity must logically start with the subject itself. In choosing our subject we should first consider how effective it would be in a small sketch, say no longer than 5 by 7 inches. Could the material be set down in a sketch of that size? Could it be done without using a very fine brush or would some of the important details be too small? If it is impossible to make a small sketch without infinite labor, then we can be pretty sure we are starting off on the wrong foot. It is safe to say that any subject that will look effective in an exhibition gallery or on the wall of an average-sized living room is also definable in a 5 by 7 inch sketch at a distance of 6 feet or more.
Even though in a small sketch we would normally only suggest the outlines and form of a subject, the patterns should be simple enough to make the design carry ten feet or more. If the small sketch will do that, we may be sure larger canvas will be effective under any circumstances. This is a very good reason for making a small statement of any subject before we invest effort in a larger once.
Assuming that you usually do most of your oil painting indoors, you will need sketches of outdoor scenes for reference. Make a small sketch for color aloe. This, coupled with pencil sketches for detail, or photographs of the spot, will provide much better source material for the final work than will an attempt to make a larger and detailed preliminary painting in the limited time at your disposal outdoors. If your sketch box is large, try using large brushes. Concentrate on color, tone and pattern. Leave the detail for pencil and camera.
If you try to paint too long and then have to go back over your sketch to "warm it up" because it looks too cold in the later light, the original color relationship will be thrown out of balance and the sketch will become progressively worse and inaccurate.
Since we are going to have to simplify most subjects anyway in the finished work, it is better to start eliminating in the sketch. If you take photographs for reference you can always put back a detail here or there in the final composition, should it seem to require it.
Sometimes a subject improved in the warmer light of late afternoon. In this case don't try to work over your original colors; start again or take some color shots. The point is not to mix two separate color versions in your final painting. Choose one or the other and stick to it. The one-o'clock lighting and color will never fit a five o'clock version. If you are seeking late afternoon effects, we can sometimes extend your time limit for the sketch by starting out a little earlier and purposely making your colors a little warmer than they appear. However, this takes considerable experience and skill, especially as allowance should also be made for lengthening shadows. Just as colors change, so do shadows, as the afternoon wears on.