Fixing Your Holiday Photos With GIMP
Redeye, Low Light
The holidays are such a great time for getting together with family and friends.I bet you take a camera along. Or better yet, maybe there's a shiny new camera waiting for you under the tree. I know I take lots of photos over the holiday season.
But you know what? A lot of my photos don't come out very good. Shooting conditions at those family get-togethers sometimes aren't the best, and you're probably distracted by watching Uncle Albert trying to sneak another glass of wine without anyone noticing. So this week's column is about how to fix those photos with GIMP.
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If you shoot lots of indoor shots with flash, you've probably seen "redeye". A camera can turn a perfectly ordinary person into a zombie demon from Antares.
Redeye is caused by light from the flash bouncing off someone's retina at the back of the eye, and back through the pupil to the camera. so you see an intensely red area the size of the person's pupil. It's most obvious for pupils that are wide open: people who have been sitting in dim light, and especially children since their pupils open wider.
Some cameras have a "redeye flash" mode, where they'll flash a few times before the real flash to give the subject's pupils time to contract. That helps, but it doesn't always cure it. And maybe your camera doesn't have that mode, or it's too much hassle to set it, or you just forget. What then?
Fortunately GIMP has a great redeye removal tool. Make a rough selection around the eyes, then call up Filters->Enhance->Red Eye Removal (Figure 1).
Why make a selection first? Because you don't want to get rid of the red everywhere (Figure 2) -- just in the eyes.
Shooting indoors in low light
Another way to avoid redeye is not to use flash. And sometimes you can't use flash, for whatever reason. But how do you make those low-light photos come out better?
The problem with dim light is that the camera has to hold the shutter open a long time, so the photos get blurred either because the subject moves, or you move the camera. Sometimes that creates an interesting effect, especially on Christmas lights (Figure 3) ... but most of the time it's not what you want.
Blurring is something you can't fix properly after the fact, alas. If it's only slightly blurry, you can try Filters->Enhance->Sharpen... or Unsharp Mask... but it can't work miracles.
What you can do is tell your camera to use a shorter exposure.
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