This week I am recovering from last weekend’s plein air-excesses at a Kathleen Dunphy workshop. Kathleen paints wonderful landscapes. I’ve admired them for a long time, and like most workshop attendees, I hoped she could transmit (directly into my head, thank you very much) a bit of the magic she uses to weave her paint-on-canvas spells.

But learning to paint isn’t as simple as sticking your head in a pensieve. Plein air skills are gained by—and you knew this already—long hours behind the brush, direct study, and hard hard work.

Plus, plein air painting is not a picnic in the park. The weather was hot. There were chiggers. There was wind. There was the siren-song of wineries that we had to ignore. The standing joke among workshop attendees: If painting is so relaxing, why am I so stressed?

However, it wasn’t all stress. There was lots of learning. Here are 7 valuable lessons that came home with me.

1. Squint It helps you see the values.

2. Apply the paint thinly I never realized this. I am first and foremost a watercolorist; the gloppiness (and messiness) of oil paint has always confounded me. After half an hour in the field, my canvas, clothes, face, hands, and hair are smeared every color of mud. But Kathleen begins a painting by applying a thin layer of paint—it looks like she’s drawing a charcoal sketch—and only builds the paint thickness as she approaches the finish. Woah! Control!

3. Squint Because values!

4. Narrow down the range  Everything—value, chroma, and color—lives much closer together in space than I understood. When painting, it’s better to stay near to the center than migrate to the extremes (kind of like life, huh?). For practice I’m going to spend a lot of time mixing paint in the middle of the octave.

5. Squint That hill on the horizon is not that dark.

6. Oil paint is not watercolor paint  As a watercolorist, I work like a stone mason, carving my darker values from the lights. But oil painters work like potters, adding layers of lighter values on top of darker values.  It was a different way of thinking. My head was addled by trying to think like an oil painter. I had to imagine my painting in reverse, like an old film negative. I needed wine. But didn’t get any.

7. Pay attention to values Squint!