Secrets of Digital Photography
Fast WB Color Correction
Included with your eBook are hundreds of original iNovaFX Photoshop Actions.
The ones that correct color mistakes alter your image by steering the color balance around.
Slightly less accurate, but much faster, the technique of white balance correcting is easy to learn.
Understanding White Balance Better:
For each camera there is an iCC-series iNovaFX Photoshop Action Filter that correct certain color white balance errors.
Suppose your images were inadvertently shot in daylight with the camera set to Incandescent white balance.
Not a good color result, in fact, sickening.
Ugly? You bet! Most people would simply toss the image away. But run your cursor over it for a real surprise. The ugly image was converted into the good-looking one nearly instantly with this Photoshop technique. Rollover. How'd they do that?
The appropriate iCC-series filter can be used to get the image back to where it should have been, but there is a fast, "approximate" method you can use within Photoshop.
White balance attempts to interpret the scene by shifting its center of Red / Green / Blue sensitivity up and down a scale of coloration defined as "color temperature." One end of that scale is rather gold, the other rather blue. When it's not set right, images like the sick flowers, above, are the result.
We all know how warm the interior lights of a house can appear to our eyes when we view the house in fading twilight. The incandescent lamps have a gold color while the post-sunset sky seems to paint the world in cool blue light. If we have been outdoors for a minute or more, the interior lights can look almost impossibly warm, yet when we go indoors, the light seems to be full-spectrum and not so tremendously warm at all.
Obviously, eyes adapt better than cameras. Using the Auto white balance setting will largely avoid problems, but it makes a white balance estimate with every shot and can be fooled by objects that have predominantly blue or yellow in them.
Digital cameras lock the white balance with the presets, Sunny (Fine in some Nikons), Cloudy, Flash, Incandescent, or Fluorescent (usually with variations).
Not all cameras have the complete range and some professional cameras let you set the color temperature directly in degrees Kelvin.
You could perform a Manual white balance in the light you are using, but many situations make doing that unlikely. With all these choices, one can easily make mistakes. Every day, millions of dollars worth of film gets shot under the wrong white balance. And when that happens, millions of photographers slap themselves in the head. Fortunately, you are shooting digital or you wouldn't be reading this...
Fixing off-white balance
Images like the sick-looking flowers against the blue wall, above, are the result. Most people would simply erase the image and save themselves the embarrassment.
Now run your cursor over the image. It will change into the correct white balance. The method for achieving this is almost as easy as viewing it.
But you will need Photoshop or an image editing program that has the same features which makes this possible.
In Photoshop open either the Curves or Levels window. There you will see three "eyedroppers". They suck up the value of pixels they click on.
The end ones are used to establish the light and dark points of the image, and the middle one is used to establish the gray point of the image. That's the one which will help fast-fix the shot with the poor white balance.
Or, Hunt for the Gray...
Select the middle eyedropper and click it on anything you think should be gray. The relative brightness of the gray object isn't terribly fussy. Click around until you find a pixel that brings the rest of the image into decent coloration. It may take several tries.
Note: You CAN set the middle eye-dropper to a different color than middle gray for other effects. Double click on it and a color-selector will appear. As long as its reference color is neutral gray, this technique will work. You can set it to neutral gray by making each RGB value =128 or 50%, or by entering 50% into the B-field of an HSB (Hue, Saturation, Brightness) setting while setting the H and S fields to zero.
If your shot simply doesn't have an appropriate neutral pixel in it, another nearby shot may. In the example above, the wall of gray stones helped, but almost anything such as pavement, walls, tires, paper, clothing, tree trunks, whites of the eye, teeth, trim on a house, curbs, sidewalks, pidgeon feathers, pets, or clouds may work.
Before you close the Curves or Levels window you can go to the individual Red / Green / Blue channel windows and adjust the gamma point by hand if you wish. This also has an effect on the color of the image, and the Red and Blue ones make the most white balance-like differences.
If you can fix one shot in a series, you can fix the rest. Before you dismiss the Curves or Levels window, you can Save your "discovered" correction and bring it into another shot--the one that didn't have a convenient gray object in it, for instance.
This shot of an individual flower had no gray reference in the frame. All the pixel hunting in the world wouldn't have brought it around. But it was brought into a more color-correct result by recycling the setting from the shot that included the wall of stones. Touch it with your cursor to see the result.
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