- Histograms make muddy pictures history
- Fixing color casts
- Banish Red-eye
- The magic of cropping
- Straightening perspective fixes
- Fixing Blemishes
- Bringing out detail in shadows and highlights
- Quick and soft selections
- Reuse a selection
- Whiter teeth
- Smoother skin
- Facelifts without surgery
- Quick Layer fixes
- Non-permanent fixes
- Depth of field effect
- More interesting skies
Fixing color casts
The same Levels dialog can be used to fix a photo with a color cast problem. When you photograph an object indoors, in artificial light, you should set the camera's white balance to compensate for the color of the light. For example, incandescent household bulbs typically throw a yellow/pink color and fluorescent tubes throw a cooler blue/green light, all of which will be visible in your photos if you haven't compensated for it. To remove the color cast, you'll want to use the eyedroppers in the bottom left of the Levels dialog.
Start by clicking the Set Black Point eyedropper (it's the leftmost one) and then click on the part of the image that should be black. You should see an immediate change in your image. If it's not a positive improvement, click somewhere else—but remember, you can't undo this, so if you make it worse, you'll just have to keep clicking until you find a spot that really should be black.
Repeat this process with the Set White Point eyedropper and, this time, click on a part of the image that should be white. Follow the same guidelines I gave you for the Set Black Point eyedropper.
Finally, click the Set Gray Point eyedropper and click on an area of the image that should be a mid-gray. When the result is what you want, click OK to confirm your choice. For images with a color cast this is a relatively simple, yet very effective fix.