Red-eye is light reflected back from your subject’s eyes. The bright light of your camera’s flash passes through the pupil of each eye, illuminating the blood-red retinal tissue at the back of the eye, which is reflected back into the camera lens. Red-eye problems worsen when you shoot pictures in a dim room, because your subject’s pupils are dilated wider, allowing even more light from the flash to illuminate the retina. (See the top picture in Figure 8-6 for an example.)
If it’s too late to avoid red-eye to begin with (by using an external flash, for example), and people’s eyes are already glowing evilly, iPhoto’s Red-Eye tool lets you alleviate red-eye problems by digitally removing the offending red pixels. Here’s how:
Open your photo in Edit mode.
Change the zoom setting, if necessary, so that you have a close-up view of the eye that has the red-eye problem.
Use the crosshair pointer to select the face (by dragging a box across it).
The more face you select, the better the tool does, since it distinguishes red from almost-red by comparing the eyes with the facial tones. So grab a generous number of pixels, including the eyes.
Click the Red-Eye button.
(The Red-Eye button is dimmed until you’ve actually selected a portion of the photo. If you’re editing in a separate window, as shown in Figure 8-6, you may have to use the >> menu at the right end of the toolbar to find the Red-Eye command.)
iPhoto neutralizes the red pixels, painting the pupils solid black.
Of course, this ...