The use of flash can help you capture photos that would otherwise be impossible, and can be used as fill to soften harsh lighting conditions. However, it can also cause an all-too-common problem when taking pictures of people. I am talking, of course, of the familiar red glare we call “red eye”. Even special flashes designed to dilate the pupils before the actual picture is taken often fail to eliminate this annoying problem. If your camera does not have one of these flashes, there's no need to worry. Removing red eye is a simple process that you can take care of with a few clicks of your mouse.

Without getting too technical, red eye is caused when the light from a flash is bounced off the back of the eye at an angle returning it toward the lens. When the flash is close to the lens, the reflected light goes directly into the lens, resulting in red eye. As a result, it is difficult to avoid red eye with many point-and-shoot cameras where the flash is located very close to the lens. Fortunately, correcting red eye with today’s digital tools is quite easy.

Many basic photo-editing software packages make it remarkably easy to correct red eye in your photos. For example, Adobe Photoshop Elements includes a Red Eye Brush tool that can be used to simply paint away red eye. Select the Red Eye Brush and choose a soft-edged brush. Zoom in on the pupils that exhibit red eye and position the mouse over the pupil so you can judge an appropriate brush size necessary. Set the brush size from the brush size dropdown on the Options bar or by using the left and right square bracket keys (“[“ and “]”). When you paint over the pupils, Elements will automatically remove the color, restoring the pupils to their natural black without eliminating the subtle tonal variations within the eye.

There are two similar ways to correct red eye in Photoshop. The first is to paint directly on the image, and the second is to paint onto a separate layer. I’ll cover both methods and allow you to choose which works best for you. 

If you want to correct the red eye directly on the image, you’ll need to change the default behavior of the Brush tool so it will correct the red eye without creating featureless black pupils. To use this method, select the Brush tool from the Tools palette (or by pressing “B” on your keyboard). On the Options bar, select a soft-edged brush from the Brush dropdown. Then set the Mode to Color. This is the most important setting, as it will cause the painting you perform to only adjust the color of the area you paint over, without changing the tonality. In other words, it will eliminate the red color without a loss of subtle tonal variations within the pupil.

Set the colors to their defaults of black and white by pressing “D” on your keyboard. Be sure black is the foreground color on the color picker on the Tools palette. Bring your mouse pointer over the eye, zooming in so you can clearly see the pupils, and adjust the brush size using the left and right square bracket keys (“[“ and “]”). It should be no larger than the pupil area you need to correct.

With your brush set properly, simply click on the pupil and drag around slightly to be sure you cover the entire pupil area. Be sure not to drag over the iris, or you’ll desaturate the color in that area of the eye as well.

Even though red eye is something you want to eliminate permanently, I really prefer working with layers rather than altering pixels directly. This is the second method of cleaning up red eye. The process is very similar, with minor changes required because you are working on a separate layer.

To start with this method, first create a new layer above your Background image layer by clicking the New Layer button (it has a blank sheet of paper icon on it) at the bottom of the layers palette. With this layer selected, change the Mode to Color with the dropdown at the top of the Layers palette (not on the Options bar). This will cause any pixels placed on this layer to only affect the color of the underlying layer.

Select the Brush tool and set the colors to their defaults (press “D”), making sure black is set as the foreground color. On the Options bar, select a soft-edged brush. However, set the Mode here to Normal. The Color Mode is being used for the layer you’re painting on, not the tool itself. Zoom in on the eye and set an appropriate brush size using the left and right square bracket keys (“[“ and “]”).

With the settings established, paint over the pupils to clean up the red eye. The red will magically disappear, because you are painting with black onto a layer that will only adjust the color of the underlying image layer.

I always recommend getting the picture perfect in the camera, but in many cases you’ll experience unavoidable problems. While red eye can certainly be avoided if you can get the flash far enough away from the lens, that isn’t an option with many cameras. Fortunately, you now have some tricks for effectively solving this common problem.

Source: Tim Grey / Take Great Pictures