Zoungy asks: "What's the term for painting each area to completion, rather than painting the whole area broadly with pale washes and increasing the depth?"
Answer: "Some people call it "window shading," especially oil painters. I usually call it "area-by-area painting" when it's in oil and "ink-jetting" when it's in watercolor.
For example, I want to paint this diner in watercolor. I start with a pencil drawing to give a baseline scaffolding. While I'm doing that step I notice that a couple of the cars have already been replaced by new cars.
It has an active parking lot. Patrons stay inside for an average of 45 minutes (according to Google). I decide to paint the motorcycles first and then record the parked cars one at a time.
The rendering grows outward from those finished areas. I can worry about the sign and the trees after I finish the parking area.
Ink-jetting is just another painting strategy that every painter should try and have ready when you need it, in contrast to the "overall approach" advised by Pissarro and others.
Area by Area Painting
Pissarro's Advice to an Art Student