Photoshop CS4 Extended—amazingly the eleventh version of this flagship application—is a solid upgrade, perhaps more so than CS2 or CS3 was to its predecessors. Some of the advances that were begun in CS3—such as 3D effects—have developed further in CS4 and the attention-grabbing advances in utilizing graphics processing units (GPUs) represent major new initiatives leveraging cutting-edge technology. Whether or not these groundbreaking advances convert to improvements in day-to-day work is another question.
Photoshop CS4 allows you to rotate the canvas within the interface, making drawing and painting easier. The little compass icon is also cool though a little superfluous. Click the image for a larger view.
Photoshop now taps into the power of GPUs and OpenGL to create some excellent increases in speed and handling:

The pixel grid shows up when images are zoomed to 600% or higher.
I also find that you need a very good computer to take full advantage of these performance gains. I use a MacBook Pro with a 2.33GHz processor, 3GB of RAM and a compatible GPU but movement is still choppy sometimes. Those with older machines may not enjoy a speed boost at all. I think these advances will really come to fruition in a few years, when more personal computers can get full use out of them, but for now Photoshop CS4’s performance can be a mixed bag.

The Adjustments panel is Photoshop CS4’s new command center for adjustment layers, including a few new ones like Vibrance.
Perhaps the two most visible changes to Photoshop CS4 are the new Adjustments and Masks panels. In my “First Looks” articles on CreativePro.com, I said my initial impression was that these panels did not really offer a tangible improvement to the application. After a few months of thought on the matter I think I can temper my comments by saying that these two panels do have their uses—but only in a limited way and for a limited group of Photoshop users.
The Adjustments panel’s great contributions to Photoshop CS4 are its new Vibrance adjustment and the preset list. The Vibrance adjustment has been carried over from Camera Raw technology and is very useful for delivering added punch to an image. Advanced professionals will probably want to use more exact tools such as Curves but Camera Raw users will like the slider functionality that they’re used to. The presets are no more revolutionary than the tool presets we’ve had for years but the kind of automatic adjustments that in the past were best produced by the Actions panel are now more logically produced from the Adjustments panel. This panel is now the nerve center of adjustment layer production in Photoshop.

The Masks panel works best when non-destructively tweaking masks; density and feathering are both controlled.
In my “First Looks” article I harped about the Masks panel, since it only has two features that were not in previous versions of Photoshop (the Density and Feather sliders, which constitute the non-destructive aspect of the Masks panel). There’s something to be said for non-destructive masks—the Adjustments panel is also all about non-destructive changes to an image—but my own masks are usually either one of two types: hastily brushed and just as easily deleted and brushed again, or masks derived from image channels, which do not require many tweaks
The Masks panel is actually quite helpful for the channel masks, which sometimes need blurring in order to be effective; the Feather slider produces a non-destructive blur that is very useful. Advanced users will probably find relatively little benefit in the Masks panel, but there are a few little improvements for them—and even more for beginner and intermediate users. I feel the Adjustments and Masks panels were designed with them in mind.
The Dodge, Burn and Sponge tools have been improved so they don’t damage tone and color, which everyone tells me is a great improvement. I was never too bothered by the previous Dodge and Burn tools and I found them helpful from time to time, though they were always too powerful for what I used them for and often applied them with 10% exposure. But the new tools’ algorithms are definitely improved: applying the Dodge and Burn tools now look like they are handling exposure rather than dumping black or white on an image. The Sponge tool set to “Saturate” actually works really well now as a spot saturation tool—try it on some of your portrait shots to bump up fleshtones.
Photoshop CS4 has a few features that I would consider major advances in technology, but my choice for the most game-changing advances would be those in alignment, blending and warping, culminating in the impressive Content-Aware Scaling. I use these new features from time to time and I know they make some Photoshop users’ jaws drop. Photoshop CS3 had the Auto-Blend and Auto-Align features, which were often used to magically remove objects from series of images, but the technology now shows up in applications such as panoramic stitching (Auto-Blend has improved the blending and masking of edges), depth-of-field improvements (combine a series of photos with various depths of field to create a single image with deep focus) and “smart-scaling” images.
Content-Aware Scaling is easily the most jaw-dropping feature in Photoshop CS4. Here the original image (left) has been horizontally scaled almost 50%, yet the new image (right) looks natural. Click the image for a larger view.
This last feature is powered by Content-Aware Scaling, a new magic in CS4 that lets Photoshop judge which parts of an image can be scaled and which need to stay in proportion. The end result is an astounding new feature that allows you to scale images with the assurance that important elements will not be distorted. I’ve tested this quite a bit and, for almost all purposes, Content-Aware Scaling will not fail you. Even for major scaling operations, you will preserve almost all major image elements. Content-Aware Scaling works best on images that have some open areas that can be distorted, such as landscapes and images with open backgrounds. On the other hand, Content-Aware Scaling cannot preserve all elements in an image, nor can it do well when the change in proportion is extreme. However, in 99% of cases this is a moot point and Content-Aware Scaling will make the perfect image for you. I was never dissatisfied with its performance.
Quick Tip: If you use Content-Aware Scaling on an image and find that it wants to distort the subject, try masking what you want to preserve with Quick Mask or a layer mask. Then, when using Content-Aware Scaling, select the alpha channel in the Protect drop-down menu in the Options bar. There is also a button that will help you protect fleshtones.


[...] My recent review of Photoshop CS4 Extended dinged the Adjustments and Masks panels, which I thought were not much more than repackaged features that Photoshop already had. I wasn’t sure the change was necessary for Photoshop’s advanced user base. In contrast, Photoshop Elements sports a new tool that leverages pre-existing tools but has a much stronger rationale. The Smart Brush, which is basically a combination of the Quick Selection tool and adjustment layers, simplifies the selection and adjustment process for beginner and intermediate users. The Smart Brush is a helpful combination of selection and adjustment technology. Click the image for a larger view. [...]
[...] Some of the CS4 applications I’ve reviewed have been somewhat disappointing (Photoshop) while others have turned out to be radical upgrades with varying degrees of success (Dreamweaver, Flash). InDesign CS4 is, in my opinion, one of the best upgrades in CS4 suite: none of its new features really miss the mark, and most of them are quite useful (and a few are excellent advances in InDesign’s evolution). In my daily work I use InDesign CS4 more than probably any other Adobe application, and it has been a treat to use. [...]
[...] and productivity as fewer new tools and cool technologies have been included. In my reviews I considered this shift detrimental, but according to third-party research commissioned by Adobe productivity [...]