At some point, I noticed that some of my paintings looked quite different on site, ‘en plein air’, where I painted and first photographed them, than they did later that night, back home in electric light.

What was causing this phenomenon?

I theorized, it might be due to simultaneously intense color contrasts and low tonal contrasts in the painting. Consider, for instance, the autumnal rosy grass and medium green bushes in the top version of the landscape shown in this post. These colors are near compliments, nearly opposite one another on the color wheel. But tonally, they are quite similar, neither one being very light or dark. When viewed in low light hue, or color family, becomes less important to our perception than the relative lightness and darkness of colors, or tone. These particular colors have very similar tones. The two adjacent color fields, where they appear in the middle distance of the painting, melt together into a new shape, in electric light, as seen in the lower photo, here.

But I think more may be going on. Perhaps some pigments stay light and almost reflective in low light because of compounds mixed into them, like fluorescents, metals, or glass, acting like a bicyclist’s yellow safety gear—while others merely absorb light. Maybe that’s what’s going on in the clouds. The clouds the horizon in the daylight image of the painting appear much darker when the painting is viewed in electric light.

Next step—I’m going to make a color chart from the limited palette I take with me when I paint outdoors and see how they look, later, in electric light.