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Content-Aware Scaling in Adobe Photoshop CS4 with Martin Evening - Martin Evening was recently given the honour of appearing in the Photoshop Hall of Fame. Here he shows us how to use the Content-Aware Scaling tool in Adobe Photoshop CS4.
|Martin Evening receiving his award.|
"Content Aware Scaling is really easy to use. The only limitation is the speed of your computer and the amount of RAM you have," said Martin Evening, author of the forthcoming Adobe Photoshop CS4 for Photographers: The Ultimate Workshop and recent inductee to the Photoshop Hall of Fame.
"Content Aware Scaling works by the tool first analysing the image looking for patches of low frequency (featureless) detail and builds an effective jigsaw of roughly-shaped vertical and horizontal slices. When you stretch or compress a photograph, most of the compression or stretching is applied to the slices that contain the low frequency detail. There is also built-in detection for circle shapes, so that you can for example, compress a car, but without squashing the shape of the wheels. Plus, there is a skin tone feature which allows you to stretch or compress portrait images more effectively."
The tool can be very useful particularly for certain types of jobs. There is obviously a gimmick factor to this feature and it's certainly fun to play with and apply extreme stretching or compression to photographs. That of course may well worry some photographers who are perhaps rightly concerned about art directors or designers fooling around with their images. However, I don't think this is a completely new situation in digital image retouching and as always it's important for the photographer to assert their moral rights for a picture not to receive what is referred to by copyright law as 'derogatory' treatment.
From my point of view I work for agencies where I'm in control of the retouching. I can certainly see it as a useful tool where you need to take a standard photo and adjust the aspect ratio to suit several different layout formats. So where the image creator is in charge of the retouching I think it's a very useful tool to have."
The Content-Aware Scale feature is arguably one of the more interesting, and some might say, controversial new features in Photoshop CS4. As you can see here, you can use content-aware scaling to radically adjust the aspect ratio of some photographs, but without squashing or stretching important subject matter within the picture. Yes, this may be a contentious tool if used inappropriately and without permission of the copyright holder, but we feel it may prove very useful to photographers who work in design and advertising. For example, most ad and design layouts are required to fit several different aspect ratios such as posters, magazine layouts and web banners. This tool allows you to easily modify a single photograph to fit various aspect ratio layouts.
1. Here you can see the original photograph shot of a harbour entrance.
|Photo: © Martin Evening.|
To prepare this photograph for content-aware scaling, I first need to select all on the Background layer to target the image for transforming.
2. I then go to the Edit menu and choose Content-Aware Scale (or I could use the Command+Option+Shift–C [Mac] Control+Alt+Shift–C [PC] keyboard shortcut). This applies a bounding box to the image and allows me to drag the right hand side handle inwards to compress the picture horizontally. You'll notice in this screen shot how the content-aware scaling feature cleverly compresses all the soft areas of detail such as the harbour wall and the sea, while preserving the detailed subjects such as the lighthouse and boats.
3. After I've applied the first content-aware scale transform I select the crop tool to apply a crop to the photograph where I drag the top handle of the crop bounding box upwards and click OK, in order to add more canvas area to the top of the picture. I once more chose Edit>Content-Aware Scale so that I can apply a second transform to the photograph.
4. Here you can see the result of the second content-aware scale transform, in which I dragged the top handle of the transform bounding box upwards to make the image fill the full height of the picture. What is interesting about this feature is the way that the content-aware scale transform appears to automatically recognise objects where the shape needs to be preserved, while compressing or stretching the areas that are of less importance. You'll also notice in this example how the content-aware scale transform preserves the position of the horizon and stretches the sky only.
|Photo: © Martin Evening.|
This tutorial is an extract from the forthcoming 'Adobe Photoshop CS4 for Photographers: The Ultimate Workshop' book, by Focal Press. Due for release in March 2009.