Sometimes photos are too light or too dark. You can use the Enhance tool to have iPhoto automatically adjust an image’s exposure and contrast to improve its appearance. Using the tool is extremely easy.
- Click the Enhance button. The photo’s contrast and exposure are adjusted.
- Continue clicking the Enhance button until the photo begins to look worse.
- Press -Z. The most recent enhancement is undone. The photo should look as good as the tool can make it look.