Adobe made some pretty serious changes in Photoshop CS4, especially in the workspace. And while some of them, like the new Application Frame, will take some getting used to (and are optional), they’re changes that are long overdue. Each new version has piled new tools on top of old, and important bits and pieces were getting lost in the shuffle. In fact, you’re liable to see several “new” tools in Photoshop CS4 that aren’t really new at all (like the Hand and Zoom tools); they’ve merely clawed their way back to the surface after being buried. As a result, a few tools have been cut (stay tuned to find out which ones).

There’s no shortage of new features either. Photoshop CS4 takes advantage of OpenGL—a hardware and software engine for drawing graphics faster and more efficiently—to render some very slick and useful screen effects like Rotate View, pixel tossing (called Flick Panning), dynamic brush resizing, and more. Also making its first, tentative steps in CS4 is a new technology called seam carving, the engine behind the new Content-Aware Scaling tool that intelligently resizes your images so your focal point remains unchanged. Along with it comes a real 3-D engine, new Masks and Adjustments panels, selective editing in Camera Raw, and more. What’s missing in this release, however, is 64-bit compatibility—the means by which Photoshop can handle files greater than 4GB in size. Windows Vista 64-bit got it, so why not the Mac? Read on to find out why.

New way to work

Your Photoshop Life can now exist within a compact frame you can move around and resize (it’s on by default). The upside of using the Application Frame is that all of Photoshop’s windows and panels stay together as you move things around, and resizing the frame automatically resizes your panels and windows to fit inside the frame (which is great for sequestering Photoshop to one portion of your 30-inch Cinema Display). The downside is that this kind of view is a radical change for Mac users, because it looks very PC-like.

At the top of the frame you’ll spot a new row of tools called the Application Bar. It gives you quick access to the new Arrange Documents menu, which lets you see and work with several documents at the same time, as well as the sparkling new Rotate View tool. By using Rotate View you can spin your canvas—not the pixels—in order to work with it at an angle (tablet users have been begging for this since it debuted in Corel Painter (( ); http://www.macworld.com/article/59982/2007/09/painterx.html) a few versions back. The Application Bar also makes other tools easier to find, like those buried deep in a menu (Rulers, Guides, and Grids are now available in the Extras menu), at the very bottom of the document window (Zoom Levels), or at the bottom of the Tools panel (Hand and Zoom tools). Workspace presets also get top billing at the top right of the bar. Take the What’s New in CS4 workspace for a spin to highlight (literally) all the menu items new in Photoshop CS4.

You can also create even more room for your images by collapsing docked panels with a single click, and moving around within your images has also been improved with smoother screen display at odd zoom levels and the ability to “toss” your pixels with the Hand tool (called Flick-Panning). A bird’s eye view Quick-Zoom lets you instantly fly out of a high zoom view by pressing H while the Zoom tool is active (very handy when you’re working on fine detail and you need to see where you are, or quickly move to another area). If you zoom to 501 percent or over you’ll see a pixel-grid enabling you retouch images with precision.

Another useful addition is spring-loaded tools. By pressing and holding a tool’s keyboard shortcut, you can temporarily switch to it and perform your edits, and then release the key to return to your original tool.

New masks and adjustments panels

Adjustment layers have long been the tool of choice for nondestructive editing, though they weren’t especially easy to find, nor were their presets. Now adjustment layers take center stage in their very own panel, which not only makes them easier to find and use but it prevents images from being obscured by dialog boxes. Also new are “on-image” adjustments for the Curves and Hue/Saturation adjustment layers. Instead of making a selection, you can apply the adjustment to a specific tonal range by clicking on the image and dragging with your mouse. You’ll also find a new Vibrance adjustment layer which will make your colors pop without damaging skin tones (it has more effect on brighter colors and less effect on light colors, like skin).

The new Masks panel also makes layer masks easier to find and a bit more friendly. After you’ve made a selection you can create a mask from the panel and feather it with a handy slider. Adobe also added buttons for Refine Edges and Color Range functions for more mask tweaking.

Content-Aware Scaling

Using the simplistic controls of Free Transform with the revolutionary new seam-carving technology under the hood, Photoshop analyzes your image and alters unimportant areas, like the ground or sky, while leaving the important parts (like Aunt Edna’s smiling face) intact. Affectionately referred to as CAS, it works on image layers and selections in RGB, CMYK, Lab, and Grayscale color modes at all bit-depths (bit-depth refers to the number of color values a channel can contain). But does it work perfectly? No. You’ll see artifacts in some images, which means you’ve got to be really picky about when you use it (no tight portraits), and how much scaling you do (very little). You can, however, give the tool a little help by protecting your subject with an alpha channel first. Still, this function has many practical uses like fitting an image into a small space without cropping, prepping an image for a certain output size when the original aspect ratio isn’t quite right, and more.

Enhanced color and painting tools

Graphic designers will appreciate Kuler integration, an amazingly useful, online community-driven color theme generator. If you get stuck trying to choose a color palette for your design, pick one from the growing number of shared themes (feel free to join the fun and upload your own). Retouchers will be happy to know that the Dodge, Burn, and Sponge tools—long considered too destructive for use directly on an image—have been reengineered to intelligently preserve color and details, and the Clone Stamp and Healing brushes now show a live preview—inside the brush cursor—of the sample area you’re about to apply. You can also resize any brush-based tool by Control-Option-dragging or change the hardness by Control-Option-Command dragging.

Camera Raw 5.0

The newest version of the Camera Raw plug-in sports major improvements like the ability to edit selectively using an Adjustments Brush, apply nondestructive Gradient Filters, and perform post-crop vignetting.

Selective adjustments are incredibly easy to use; just select the Adjustment Brush by pressing K on your keyboard and you’ll see the same set of slider-based adjustments appear on the right side of the window as you do when you first open Camera Raw. After you brush across your image to apply the adjustment, a green push-pin marks the area. Behind the scenes, Camera Raw creates a mask that hides the adjustment from the other areas of your image. This means you can continue to tweak the adjustment sliders even after you’ve finished painting. You can click the little plus and minus signs on either end of the adjustment sliders to lessen or strengthen the adjustment, turn on the option to view the mask as well as change the mask color. By enabling Auto Mask you’ll confine your adjustment to brush strokes that fall upon areas of similar color. Masks are fully editable and you can make as many masks as you want or delete them.

Also new is the ability to apply adjustments using a Graduated Filter tool, much the like the real graduated filter you’d screw onto the end of your camera lens. You get the same set of adjustments as you do with the Adjustment Brush, though with the Graduated Filter tool you apply them by clicking and dragging (you’re really doing is creating a gradient mask, which hides the adjustment from the rest of the image). You can continue to make adjustments even after you’ve used the tool.

New Extended tools

Photoshop CS4 Extended users will notice a couple of new tools called 3D Rotate and 3D Orbit in their Tools panel, as well as an entire menu devoted to the realm of 3D which includes New Mesh from Grayscale, Invert Visible Surfaces, and Create UV Overlays. If you’ve ever dreamt of dabbling in 3D modeling, Photoshop Extended is a great place to start. Just like you can buy stock images, video and audio clips, you can also buy 3D objects and import them into Photoshop (just do a quick Google search and you’ll find oceans of 3D models to experiment with).

What’s truly amazing is that if the objects are already painted and lit, you can import that info into your scene, completely intact. You’ve also got a fair amount of control over the object’s textures and lighting too. If the object came with a separate texture file, you can edit it in Photoshop and see the changes updated on your model when you save. You can also add and adjust lighting to make the model better blend into your scene. If you’re feeling particularly brave, you can paint directly on the surface of a model in real time. For 2D folks this may sound like magic, but for experienced 3D jockeys it’s old news. Though it’s really nice to have this functionality in Photoshop, especially if you don’t have a 3D painting program.

If you’re a video editor, you may appreciate the single-letter keyboard shortcuts, smooth display of non-square pixels, and the ability to preview and export audio.

Adobe giveth…

Of course there are also tons of other additions like the ability to delete layers by pressing—wait for it—the Delete key (yay!), enhanced Auto-Align and Auto-Blend commands for creating panoramas, complex composites, and extending your perceived depth of field through merging several images of the same object with different focus points. You’ll also find support for Multi-Touch trackpads on Mac laptops, color profiles for the color blind, a 6-color histogram in the Histogram panel, support for 16-bit printing, and a new online help system.

As mentioned earlier, while Photoshop CS4 is indeed 64-bit compatible on the Windows side, Mac users will have to wait till CS5. While 64-bit compatibility was on Adobe’s road map, it was developing 64-bit compatibility into the existing Carbon-based program. At its World Wide Developer Conference in June 2007, Apple announced the halt of Carbon 64 development and the intention to forge ahead with Cocoa instead. That means Photoshop for the Mac needs to be rewritten from the ground up, and Adobe says they’re working on it fast and furiously. Though honestly, 64-bit is only meaningful if you work on files over 4GB in size—the vast majority of us don’t.

...And taketh away

With the good comes a little bad: To make room for new features, some long-time, built-in plug-ins hit the cutting room floor, like the Extract Filter, Picture Package, Contact Sheets, and PDF Presentations. Thankfully, the older versions of those plug-ins still work (save for PDF Presentations) and you can download them from Adobe’s site or snatch them from your copy of Photoshop CS3. The drag and drop PhotoMerge dialog box has also passed quietly into the night, along with the ability to create a PDF of a Layer comp within Photoshop (though you can still do it in Bridge).

Macworld’s buying advice

All of the changes in Photoshop CS4 and Photoshop Extended CS4 add up to a friendlier, more accessible interface (and with Photoshop that’s an accomplishment), with increasingly helpful tools that are much easier to find and use than before. The changes may take some getting used to, but in the end, you’ll come to appreciate the more streamlined and uncluttered experience. If you’re a photographer, the enhancements in Camera Raw alone may well be worth the upgrade and for everyone else, the additions along with the improvements to existing tools makes for a much more enjoyable Photoshop experience.

[Lesa Snider King, founder of GraphicReporter.com, is the chief evangelist of iStockphoto.com, author of Photoshop CS4: The Missing Manual (Pogue Press/O’Reilly), From Photo to Graphic Art (KelbyTraining.com), Graphic Secrets for Business Professionals (Lynda.com), and co-host of YourMacLifeShow.com.]