Adobe Photoshop CS4 - Adobe Photoshop CS4


Many familiar Photoshop features have received a thorough overhaul. The Dodge, Burn and Sponge tools, used to selectively adjust exposure and colour saturation in particular areas of an image, have new algorithms that produce far better results. Previously using the dodge tool would often cause lighter tones to be bleached out while attempting to enhance shadow detail. With the improvement it is far better at preserving those tones.

The ever-useful Clone Stamp tool has also had a bit of a makeover. Now, when the sample point is selected the cursor shows a live preview of the pixels that will be copied, which makes it much easier to match up lines and textures.

There has also been an improvement in the way that brush sizes are changed. When using any brush, holding the Alt key and the right mouse button (Command and Ctrl on a Mac) shows a preview of the brush size and hardness, and this can be altered on the fly by simply moving the mouse. This is one of those features that is so amazingly useful that I’m surprised it wasn’t added five years ago.

One of the most impressive enhancements is to the automatic panorama stitching function that has proved to be a popular feature of the last few versions of Photoshop. The new version has much better pattern-matching ability, and also has features to automatically correct vignetting and barrel distortion, so it can produce panoramic scenes from a much wider range of starting images, and produce much better results. This gives users a wider latitude in the shots that can be turned into panoramas, and negates some of the (linkout: careful preparation that was previously required to ensure good results. The program can also stitch photos together vertically, and in another completely new feature it can also create 360-degree panoramas.

This same pattern-matching technology is used in another clever new pair of features, Auto-Align Layers and Auto-Blend Layers. Auto-align is useful if you have a series of very similar images shot hand-held or with other slight movement between frames, but where you need to align the frames so that the background is the same between shots, such as when compiling animation frames. Previously this would have been a tedious process of aligning semi-transparent layers by eye, but using pattern-matching the program now detects similar features between shots and automatically lines them up for you.

Auto-Blend is a similar pattern-matching feature, and can be used along with Auto-Align to produce a new and remarkable Photoshop effect called Extended Depth of Field. If you take a series of images of a scene with limited depth of field, but altering the plane of focus with each shot, Photoshop can merge the resulting images together into one image that looks sharp from front to back. This will be useful for macro photography, where limited depth of field is a real problem. See the sample images at the end of this review for the results.

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