The world around us, both man-made and natural, provides a kaleidoscope of colors, but often photographs are stronger when you limit that palette to just a few select colors. The reason is simple: the fewer colors that you include in a shot the more bold and prominent those colors become. In the shot of the lobster floats show here (I shot them next to a pickup truck in Stonington, Maine), by isolating the pattern so that you see just the two main colors, the pattern jumps right out at you--the contrast of just two colors strengthens the pattern of the repeating shapes. Had I included some of the red color of the truck or the yellow house behind it, your eye would start to wander from color to color instead of concentrating on the pattern of green and white.
You can apply the idea of a limited palette to a lot of subjects. In flower shots for example, a row of pink tulips will look stronger when isolated against a plain green lawn than against other colorful flowers. Or, if you're photographing a row of brightly painted blue and red rowboats on a Caribbean beach, isolating them from their surroundings (and other colors) will really make the colors pop.
Interestingly, the combination of colors that you use when you select a limited palette will have a profound effect on how each of the colors is perceived. Photograph a single green leaf against a sheet of black construction paper and the color of the leaf will "advance" forward, nearly leaping off the background; but shoot the same leaf against a red background and the two colors will "vibrate" against one another, competing for your attention. I've been doing some experimenting with color contrasts lately and will publish some of them in future postings.
6 hours ago