Getting the Best Photographic Color
As a digital photography mentor, I am often asked how to get better color in photographs. Many budding photographers are concerned that the colors in their pictures are not ideal – washed out or dull or exhibiting some kind of color cast–skin tones appear too red, etc. While color problems are common, I don’t feel that bad color is the biggest issue for most photographers. The reason the color in photographs may appear humdrum has to do with the basics of the human visual system. Let me explain:
The Camera Lens Mimics Human Vision
The human eye is a complex organ…and it’s no surprise that cameras are designed to mimic its features. The eye functions by collecting light through a lens onto a sensitive surface (the retina) the images striking this surface are converted into electrical impulses that are interpreted by the brain to form the pictures that we experience. Modern cameras have a similar functionality – they collect light through a lens onto a light-sensitive surface in the form of a CCD or CMOS chip and convert this into a digital photographic exposure.
The retina is composed of two types of light-sensitive structures known as rods and cones. Cones come in three different versions that are sensitive to narrow frequencies of light representing red, green and blue color. Rods are only sensitive to brightness and cannot distinguish color – they are, however much more plentiful and more densely packed in the retina than cones except in the very center of the retina at the fovea. Rods are also smaller and thus capable of reading more detail in the variation of light and dark. Rods are much more sensitive to light and respond in much dimmer light than cones do – one reason the color is less noticeable as the light level gets darker. The human visual system places more importance on being able to see details in dark areas that do not rely on color differences – an evolutionary advantage – obviously a good idea to be able to see that saber tooth tiger hiding in the bushes with his camouflage coloring!
The modern digital camera is actually only sensitive to brightness – color is interpreted in a post capture processing phase by comparing the different luminosities under tiny red, green and blue filters on the surface of the camera sensor. The different brightness levels also contribute to the image details in the form of shadows and highlights. Without these shadows and highlights a recognizable image would not exist – we would only perceive abstract blobs of color. Think for a moment how effective black & white photographs are. The value structure of an image is much more important than how colorful it is!
The Impact of Tone and Contrast
Most people will tolerate a variety of color renderings if the contrast and tonal range is compelling. For most photographic images, insuring that the image contains a full range of tones from black to white and that the areas of primary importance contain the most contrast (or differences between tones) is much more important than how saturated or dull the colors are.
So, if you want to create visually interesting photographs, concentrate on tone and contrast before you mess with the color. Mastering tone and contrast is the foundation of the Varis System: a new digital Zone System based on the original system developed by Ansel Adams.