PS CS4: What's New — Content-Aware Scale

Well folks, here's the much touted new addition to Photoshop — a way to shrink or expand your image's dimensions while keeping the scale of your subject(s) untouched!

Frankly, I've had mixed results with it. Left to its own devices, its supposed to "automatically" recognize what the subject of the image is — well, maybe. It depends a lot on the composition. If the background is a bit "busy", ain't gonna happen.

In those cases, there are methods (see below) to force the recognition. Even at that, though, the results are mixed and I look forward to significant improvements in CS5. Apart from that, it's still kind of cool.

Here's the image we'll be messing with. The subject is circled in red and what I want to do is shrink the dimensions.

The Usual Way

All we've done here is Cmd-T (Mac) or Cntl-T (Wind) to bring up the Transform Tool and pull in the left and right handles.

This is the "old" way and will be used here as a baseline for comparison.

Content-Aware Scale on Automatic

By pressing Edit > Content-Aware Scale, you get your image surrounded by the usual handles on the corners and sides, which you can move in or out to re-dimension your image. Note: If you try to do this on the Background, you must select it first (Cmd-A on a Mac or Cntl-A for Windows).

As you can see, the derned thing didn't recognize the subject at all. In fact, the results are worse than doing it the "old" way. The guy to the right of the subject looks like he's made of spaghetti.

Scaling Options I

There are a couple of ways to force the thing to recognize the subject, and here's the first.

Use any selection tool you like and place a selection around the subject.

Now press Select > Save Selection. When you do this, a dialog box will ask you to name the selection, which I've named as "subject". This will create an Alpha Channel with that name. You now need to find the "Protect" drop-down menu and select that same name (both circled in blue). This will prevent your selection from being scaled.

You can now set your Amount percent, circled in red. Zero percent means, basically, don't do a thing, do it the old way. Here, I have it set at 100% to fully maintain the original scaling of the subject.

You can also preserve skin tones by clicking the icon circled in green — sometimes in scaling, the skin tones go a bit nuts.

Results

After doing all the stuff, above, I shrank the image again. As you can see, the suject's dimensions were very well preserved.

The guy on the right still looks like spaghetti, though, so we have to resort to our ultimate fall-back position.

Scaling Options II

The Amount percent affects the entire image, but there is a way to selectively determine how much each area of your image will be scaled. And the answer is — create a mask.

The magic of creating a selection with a mask is that you can control the opacity of your brush strokes. It's real hard to see in this image, but if you look down to the bottom of the Channels Panel, you can (barely) see that the people to the left and right of the subject were painted with a brush set at 50% opacity (the gray blobs). The subject is white (no scaling effect), and all else is black (scale 100%)

Hopefully, what this will produce is a subject that is not scaled at all after shrinking, and the folks to the left and right scaled just a bit (the rest of the image should squeeze in completely).

Results

Well...sort of. The person to the left scaled just a bit, as we predicted by paining a mask with 50% opacity. Unfortunately, Mr. Spaghetti man is still Mr. Spaghetti man. Ah well.

This does have promise, though. I'm not giving up on it just yet. As I said, a lot depends on the nature of your shot and how much you want to scale. I'm not quite ready to shoot off fireworks over this new feature, but I does have promise. I'm just not at the Oooo and Ahhhh stage yet.