The Faces feature in iPhoto is useful, but how does it work?

Digital cameras recognize faces as an arrangement of shapes, and they use this to select the best focus and exposure settings for the picture, on the assumption that any faces will be the most important part of the image. Only a few cameras take the next step, which is to try to distinguish one individual from another on the basis of their facial features, but this is the basis of iPhoto’s Faces system.

It works in two stages. First, it scans your photos to see which, if any, have faces in them. It then attempts to group faces by likeness, and match any new faces to those you’ve already identified.

It doesn’t get it right every time, and you have to train it by manually identifying or confirming the identity of your subjects. But it does learn, so that the more you train it, the better it gets at recognizing particular people. Of course, you might go along quite happily without using this Faces feature at all. If you’ve got a library of thousands of photos, the prospect of trawling through them all looking for and identifying every single individual is daunting.

But you don’t have to look for faces throughout your whole library. You can look for specific individuals and ignore the rest. You could even create smaller libraries for this job. Our walkthrough shows one instance where this works very well. It’s a library consisting of old photos scanned in then imported into iPhoto. What iPhoto can do is bring together pictures of people who may appear in dozens of unrelated prints taken over a period of many years. It can also help you identify people based on who they’re with, or by the context they appear in. You can see connections that you wouldn’t spot simply by leafing through prints.

What can be confusing about Faces is that there are different ways to identify and confirm them: from the Faces corkboard via the Find Faces button; by double-clicking a face on the corkboard and checking to see if iPhoto has found additional photos where they might appear; or by opening a photo, displaying the Info panel and seeing who’s been recognized. Each has its pros and cons, but they’re all just different ways of doing the same thing, and it really doesn’t matter which you use.

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Identify Faces in Your Photos

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  Scanning for Faces

  When you import photos, iPhoto scans them for faces. This happens in the background, and might only take a minute or so. If you’re upgrading an old library, though, or creating a new one from scratch, this scanning process could take some time.

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  Naming Faces

  If you’re using Faces for the first time, clicking Faces in the source panel displays the faces iPhoto has found in sets of three. Click below each one and type in a name, then click the Show More Faces button bottom right to see the next three.

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  Faces Corkboard

  As soon as you start identifying faces, iPhoto displays them on the "corkboard". This is what you’ll see when you click Faces in the source panel. Now you can click the Find Faces button on the bottom toolbar to go back to the previous screen and carry on identifying faces.

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  Photos of One Person

  Alternatively, say you want to find more photos of a particular person. If you double-click on their face on the corkboard, iPhoto displays thumbnails of pictures where you’ve so far identified them. But it tries to identify other photos it thinks they might be in too.

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  Photos or Faces

  There’s a switch at the top right marked Photos/Faces. Use this to display only faces of the people you’re identifying (see the previous screenshot) or the entire photo they appear in. Click the Confirm Additional Faces button, bottom right, if needed.

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  Confirm More Faces

  iPhoto will display thumbnails of all the other instances where it thinks that person appears. Click on a face to confirm it, and option-click if it’s not the face of that person. You may need to go through this a few times as iPhoto expands the list of possible matches.

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  Checking Faces in Photos

  Now for the third way of adding names to faces; this can be useful with group shots – who else is in the shot can often tell you who the person is. Open the photo as normal and open the Info panel. Recognized faces will then be identified, with their names underneath.

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  Adding New Faces

  You can enter names directly in the boxes below and, if a face hasn’t been identified at all, click the Add a face button in the Info panel, and drag the marquee over the face; resize it by dragging on the corner handles. Now you can type in the appropriate name.

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  Quick Tip

  Sometimes iPhoto sees faces where there aren’t any. We don’t know what it saw under this deckchair (creepy!), but it’s certainly not human. If this happens, just click the close box (the cross in a circle) at the top left of the face marquee.

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