Fixing Your Holiday Photos With GIMP
Redeye, Low Light

Akkana Peck
Tuesday, December 22, 2009 10:03:24 AM
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.

figure 1
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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Fixing Redeye
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.

figure 2
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.

figure 3
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.
Next: Exposure Settings, Healing Blemishes »