These two photos of two of my most recent paintings give a better sense of the size of the water color sketches to the finished work. For these two acrylics, the sketches are about 1/4 the size of the finished work.
With the large watercolor I did of the Amonoosuc River, the ratio was more like 7 1/2 to 1. At this point, I don't do a detailed scale down or up from sketch to finished painting, it is more just a part of the process. Trying to keep this as simple as possible for quick and efficient sketching in an attempt to capture the moments which catch my attention.
I'm quite motivated by the idea of capturing the different moods of a subject, and even imagining them based on earlier observations of nature. Both of these paintings are realistic subjects - they do exist, but in imaginary perspective for the old mill pond, and imaging a winters evening full moon light at a local farm. I really enjoyed these different exercises in the studio. Working on location remains my first joy in painting, but studio work is gaining in its standing and enjoyment for me.
I also try to keep the advice of two well known and highly successful artists front and center as I paint. John Stobart advised putting only as much detail into a sketch as would be needed to execute a finished painting later. This was to avoid "copying" even one's own work and maintaining room for the spark of creativity.
The late Bob Harris (Robert George Harris) was very encouraging to me through our correspondence and phone calls. One of my favorite quotes of his is: "It's important to know when a painting is done before it is finished."
I also remember vividly the original illustrations by N.C. Wyeth and Howard Pyle on display at the Farnsworth Museum in Rockland, Maine. The paintings were monumental in scale, composition, color, and use of limited detail. They knew how to lead your eye where they wanted it to go. A large area of background scumbled in with virtually no detail in no way diminished these paintings. On the contrary, the contrast made the paintings even more powerful. You really had to be on the lookout to even notice these techniques.