Aspects of white balance in photo retouching
by Susan Richmond
White balance correction means to adjust the illumination in a image 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 want to take care of, when you begin to edit your pictures, is white balance. White balance refers to the color of the light and assumes that the best light color is white. Some shots, like sunset or candlelight, do not have white light, but in general an impression of white light is desirable. Some use Photoshop's auto levels to set white balance, but that is not ideal, since auto levels just 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 images have black areas, but the palest pixels are rarely pure white).
The mid tones are the most important when correcting white balance and to help set the mid tones correctly one adds a grey card to the photo when taking the photo. A grey card is a flat piece of cardboard or plastic toned 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 set the mid tones to neutral gray. One can of course only include a gray card in the image if one intends later to crop the image
If one does not want a gray card in the image, or if one does not have a gray card at hand, one can later use dedicated software that analyzes the image and finds the color of the light and sets it to white. There are draw backs with such applications: what if there are no neutral areas in the picture to calculate the color of the light from? Some software does not need a neutral in the image, but most do to get a good result.
If you work with RAW images, you will have found that the RAW converters normally come with a control for color temperature, which means a slider to adjust the picture 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 slider is good for regular incandescent light, but not for fluorescent.
Color adjustment sliders are rarely good for correcting white balance, because the color correction will not only neutralize the gray card, but will also color the picture in an undesirable way: often the blacks become toned or the whites or both. In short one needs some neutrals in an image to set white balance. A white wall or a sheet of white paper will do well; preferably add a gray card for the mid tones.
This article is based on this article about <a href="http://photoretouchingtips.bravesites.com">White balance</a> and this one <a href="http://photoretouchingtips.xanga.com">White balance</a>
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New Unique Article!
Title: Aspects of white balance in photo retouching
Author: Susan Richmond
Email: jan@janesmann.com
Keywords: white balance, photo retouching,digital photography, photography,hobbies, arts and entertainment
Word Count: 528
Category: Hobbies
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