The Colour Photography Field Guide by Author

The Colour Photography Field Guide by Author

Author:Author
Language: eng
Format: epub
Published: 2019-03-29T00:00:00+00:00


The Color of Objects

T he second element in the equation of color is the surface struck by the light. According to its composition, it can reflect, transmit, and absorb the light selectively, and thus give an object “color.”

Leaves are green, Caucasian flesh is pinkish, a marigold is orange, and we know these are intrinsic properties of the things themselves. This is common sense, but has implications that are easily overlooked in digital photography when color is being adjusted. The final color that we see, and that the camera records, depends not only on the light source but also on the surface it strikes. Because the menu settings on digital cameras place so much emphasis on measuring the color of light and adjusting the sensor’s response to it through the white balance, it’s easy to overlook the contribution of the objects in the scene.

A coat of glossy white paint reflects a high proportion of the light, transmits none (it is opaque), and absorbs very little. Most of the light, therefore, is reflected right back. A piece of black cotton velvet, by contrast, reflects hardly any light, transmits none, and absorbs most of it. This seems blindingly obvious because of the way we describe objects and surfaces. However, with the exception of white, black, and gray objects, every other surface reacts to light selectively, meaning that it favors some wavelengths—colors—more than others. Reflection and absorption work together inversely. Most fresh leaves are green because they absorb so much red. A daffodil appears yellow because its petals absorb blue.

Transparent materials transmit more light than they reflect or absorb, and when they do this selectively (like the acetate in 3D glasses) they appear colored. Moreover, the effect builds up with depth-normal glass absorbs a little red, so thick slabs take on a greenish tinge, while water absorbs first red, then yellow, and continues until, far below the surface, the color is simply blue. This effect is well known to underwater photographers, who need flash to restore the lost colors. Seawater cupped in your hand seems colorless, but 30 clear feet (ten meters) of it over white sand, seen from above, appears a strong blue.



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