This is from the book: The Oil Painting Course You've Always Wanted," by Kathleen Lochlen Staiger. I read this book to learn how a painter "sees", and hopefully this will enrich my own photography experience.
The book does credit to its title. It is a really good book for somebody who wants to get a handle in painting. I learned a lot of useful tips, such as the fact that things nearer to you have a warmer tone while the same thing in the distant horizon will appear cooler, lighter, and duller. I learn that when painting multiple ranges of hills, you darken the top and lighten the bottom of each layer. I always thought the top should be lighter (more highlighted). I also learn that to lighten colours you add white; but to darken you don't add black. You use a variety of colours, depending on what you want to darken.
Here's what may be relevant to a photographer. Staiger explains the concept of the separation of planes: "If you were to set up your easel outdoors and faithfully copy each colour you saw, your painting would look flat. That's because seeing with two eyes enables you to perceive depth." To separate the foreground, middle ground, and background, you need to exaggerate the differences in chroma, value, and hue. This concept can apply to photography. A picture that successfully separates the front, middle, and back planes (either by depth of field, selective exposure, or natural occurrence of mist or fog) often makes interesting picture.
Staiger also shows a painting that is made from a photograph. She intentionally alters the lighting and colours of the scene in a reference photograph to enhance the mood of the painting to make it more interesting. In photography we can also do the same. Hence, I learn that in order to enhance a photograph for a "painterly" (my own word) appeal, I should also do likewise. Here is the challenge: how to capture a picture as it is while not exactly as it is. Post processing seems to be an easy solution, whereby the photographer modifies the appearance with Photoshop, yet tries to makes it appear as if it comes straight from the camera.