If you’re shooting in RAW format you have the luxury of tweaking white balance as you open your images. This can allow you to adjust for camera inaccuracies or even for artistic effect. If, however, your image is a JPEG you're not out of luck.
My old D100 still takes decent pictures but it certainly ain’t fast. If I shoot RAW it literally takes eight to ten seconds to write an image to memory. When trying to take rapid fire pictures of a running greyhound this doesn’t cut the mustard (though one could argue the merits of mustard cutting). Yesterday I was taking pictures of Finney romping in the snow and found the morning light plus snow combo had confused the heck out of my poor, senior citizen of a digi-cam. Everything came out with a blue wash. Fortunately my buddy Rob showed me this common and easy technique.
Pick an area that has both black and white areas (or areas that should be white) and zoom in. You’ll be using an eyedropper tool, so zooming in will allow you to pick the right spot more easily.
From Photoshop's Image menu choose Adjustments > Levels. This will bring up the levels window with a histogram. First thing you’ll do is grab the little white tab on the right side of the histogram and start dragging it to the left.
As you drag you’ll see the image becomes more and more washed out. The goal is to emphasize the blackest of the areas on the picture. Once you’ve identified the blackest of the areas on your image you’ll use the Set The Black Point dropper (the black dropper from the levels window) to sample your new "black". Once you take the sample the image will go back to looking more normal.
Next repeat the steps by grabbing the black slider to the right. This will darken the image to allow you to identify the whitest of the white areas in the image.
As with picking the black areas, you’ll need to play with the slider to get the right contrast, then use the dropper to pick the location you’d like to define as white. Once you use the dropper the image will once again snap back to "normal". After picking the white level, however, the color issues should be largely fixed in your image. Here’s a before/after comparison of the picture with the as-shot on the left and the corrected on the right.
But hey, right next to the Levels menu item is an Auto Levels item. Why not just use that? Actually, there’s no reason not to try it out. It will often correct the color just about as well as this manual technique and take a fraction of the time. The auto levels correction, however, is not quite as accurate and I find the results from the manual method give me an image that looks much more the way I remember the scene in my mind’s eye. I do, however, often just blast through a bunch of pictures using auto level when I’m trying to speed through a big batch.
I owe two thanks to Rob for the above. 1. Thanks for showing me how to do this. 2. Thanks for taking such awesome pet pictures and inspiring me to point my camera at Finney and try to capture some of his personality.
If you live in the bay area and would like to get pictures taken of your pet, your first (and only) stop should be Murphy Dog Studios. Rob is a wonderfully talented photographer and he loves pets (his business is named after his late lab, Murphy). Don’t worry, if you don’t have a dog, or even a pet, Rob can shoot just about anything. Check out his amazing sports photography too.