Looking at a photo, and, even more, looking at a live scene, it's usually easy to tell where everything is in the space that is visible. Alas, this is not always the case once the scene has been translated into a painting. Many of the clues that are present in the source of the painting are lost in translation, often including some of the most essential ones.
In the market scene, above, the variation in size and the overlap of the figures make it pretty easy to tell who is closer than whom. But, if I tried to paint the scene just the way it appears in the photo, I am sure the space would become confusing. Consider the figure near the center of the picture, for example, the one about halfway down the block, with black pants and a light blue shirt. In the painting it's quite possible that with her high contrast clothes and fairly sharp focus, she'd float right to the foreground and end up looking like a little puppet, hovering between the two large figures in front. If I painted her with soft edges, however, she'd take her proper place, fifty feet away.
Now try closing one eye and looking at all those colored tarps. Do they start to seem like they're all in the same plane? In fact, they are all in the picture plane, but we hope to create a convincing illusion of space. Once again, some soft edges would be a big help. How do we decide how many, and which edges to make soft?
What if you made a quick study that had only soft edges, no hard edges at all? You would then have a basis for discovering where you wish you had a sharper focus. You could pretend you had a ration of three hard edges, and consider where they would have the most impact, and then proceed to add more, one at a time.
To give this a try, you'll need to soak your paper for a few minutes. Put a 1/4 sheet in the sink or tub, in cool, not hot water. While it's soaking, wet the board or table where you plan to place the paper for painting. Now lift the sheet out of the water, in and let it drip a while. Then flatten it onto the wet surface. It will stay wet much longer than if you had just wet one side with a brush, but not forever, so move right along. Block in the major shapes with a layer of their palest color. The water that is already on the paper is enough for the whole job, so keep the brush pretty dry. Adding more water will make puddles on the page, inviting the shapes to wander too much.
As you move on to the middle value shapes the paint on your brush can be thicker than the first layer. When you get to the darks, it can be even thicker. Remember, as soon as the brush touches the wet paper you are adding the water that is already there to the brush. If you see a hard edge, stop painting.
You can dry the paper thoroughly and re-wet the area you want to work on with a single stroke of a large brush. Going back and forth when re-wetting will loosen the earlier layers and make a mess.
Please bring in all your experiments.