Usually painting outside is a small, quick response to light and color before it changes, or gathering color notes for larger pieces in the studio. Sometimes the challenge of painting large is a good way to change things or venture out of my comfort zone. Usually 16 x 20 is as large as I will go and 6 x 8 is a nice size when traveling and stopping along the road for a quick sketch. But painting larger outside, 20 x 24, or 24 x 30 allows me to push the limits of what I know technically. It also forces you to just paint the heart of your subject matter because there isn’t enough time to approach it like a studio painting. It’s not always successful but keeps me from looking at everything the same way.
There are two different ways to approach painting large outside, one is to make a note of the time of day and return two or three times until you finish. The other way is to get the composition and planes blocked in, enough color notes on the canvas, then return to the studio and finish without loosing the sponteniety of painting outside.