When I lived in Cincinnati, before I had children, I tried some plein-aire painting.
The small church we attended was on a road where you would often pass cows grazing close to the road. Behind the church a meadow was easily accessed from the parking area. I took my acrylic paints and easel out there one afternoon to paint some trees. After some time, I noticed dark clouds moving into the area so I added them to the scene which was almost finished.
In the painting class I attended at the local library one evening a week, we were encouraged to try adding texture to our canvas board before we painted. This was in 1967.
Looking at this painting now where it hangs in my dining room, it appears I gessoed the board and sprinkled it with bird seed—we had a parakeet—and then scraped the seed off after it dried, because the texture under the paint is little round empty holes.
The little holes where the seed had been, creates a sparkly effect in the trees and grass because there is a light blue under painting on the entire board which is seen where the brush hits only the high parts.
The dry brush painting I did to complete the landscape also benefits from the texture where several layers of paint show through the strokes.