What is White Balance?
by Jill Zweig
White balance adjustment means to adjust the light in a picture to white. In order to do this one must have some neutrals in the image like a gray card or a white sheet of paper. Software can adjust white balance, but not all software solutions are equally good.
The first thing you might like to address, when you set out to retouch your images, is white balance. White balance refers to the color of the light and assumes that the ideal light color is white. Some pictures, like sunset or candlelight, do not have white light, but usually an impression of white light is the best. Some use Photoshop's auto levels to set white balance, but that is not ideal, since auto levels only sets the darkest pixels to black and the brightest to white without looking at the mid tones. But what if the lightest pixel in your photo is not white? Or what if you do not have pure black in the photo? (Most pictures have black areas, but the lightest pixels are rarely pure white).
When correcting white balance, the mid tones are the most important and to help set the mid tones correctly one adds a grey card to the picture when taking the picture. A grey card is a sheet of cardboard or plastic colored an exact mid tone neutral gray. Ideally one has three cards: a black, a gray and a white. Photoshop's levels adjustment panel has three eye droppers for picking color: one for white, one for gray and one for black. By clicking the gray color picker on the gray card, one can adjust the mid tones to neutral gray. One can only include a gray card in the image if one intends later to crop the picture.
If one doesn't want a gray card in the picture, or if one does not have a gray card , one can later use specialized software that scans the image and calculates the color of the light and sets it to white. There are problems with such applications: what if there are no neutral areas in the photo to calculate the color of the light from? Some applications do not need a neutral in the picture, but most do to get a good result.
When working with RAW images, you will have discovered that RAW converters generally come with a control for color temperature, which means a slider to adjust the image cool or warm. But what if the color of the light is greenish as when you have taken a picture in neon light? The cool-warm control is good for regular incandescent light, but not for fluorescent.
Color adjustment sliders are never good for correcting white balance, because the color adjustment will not only neutralize the gray card, but will also color the photo in an undesirable way: usually the blacks get toned or the whites or both. In short one needs some neutrals in an image to set white balance. A white wall or a piece of white paper will do well; at best add a gray card for the mid tones.
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New Unique Article!
Title: What is White Balance?
Author: Jill Zweig
Email: jan@janesmann.com
Keywords: white balance,digital photography,photography
Word Count: 520
Category: Hobbies
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