1: Use the Bird's Eye view
One of the nicest productivity enhancements is the Bird's Eye view feature. When you're zoomed in on an image, press and hold H on your keyboard, then click to zoom out temporarily. Photoshop draws a bounding box showing the extent of the zoomed view. Reposition the box as required, then release your mouse button to return directly to your previous zoom level at the location specified - no more panning required.
2: Refine your masks
The new Masks panel makes it easy to refine your bitmap and vector masks with editable adjustments for feather and density. Use the new Masks panel colour range option instead of Select>Color Range to speed up the process of eliminating coloured backgrounds from images.
3: Use the Vibrance adjustment
Camera Raw introduced the Vibrance adjustment a couple of releases back as a complement to saturation adjustments. Vibrance brings out the colour intensity in your image without overcooking the levels. Choose the V-shaped adjustment from the Adjustments panel, and drag the slider up as you would the saturation slider in Hue & Saturation. This adds pop to your image without burning out colour.
4: Use on-image controls with Adjustment Layers
The Hue & Saturation adjustment now enables you to click and drag to make alterations directly on your image. Add a new Hue & Saturation adjustment from the Adjustments panel then click on the button that has a hand with two arrows on it (found in the Adjustments panel). Finally, click and hold on an area of your image you want to adjust. Move your mouse in the directions indicated by the arrows to make changes. Your alterations will only apply to the range of colours underneath your cursor.
5: Adjust your image proportions
If you've got a great image that's the wrong orientation for your space, don't reach for another photo. Create an alpha channel with white paint where you want to protect your image, then size up the canvas to the shape required. Finally, select Edit>Content Aware Scale and, using small steps, re-size along one axis only. Multiple smaller applications of this transformation work best for big scales and changes on two axis.
6: Dodge and Burn like never before
It used to be that, if you weren't careful using them, Dodge and Burn could ruin photos. Adobe has rewritten these tools and they're now almost non-destructive. First of all, ensure the new Protect Tones checkbox is ticked. If it isn't, the tools act as they used to. Even with this ticked, you'll want to work at a low intensity to obtain the best results, but if you overcook an operation simply swap to the opposite tool and paint your tone back in.
7: Apply basic corrections in Camera Raw
Do your spot removal and colour correction in Camera Raw. Camera Raw now comes loaded with the option to conduct multiple localised adjustments, clone pixels with the healing tool and apply gradient mask-style adjustments. Click on the Spot Healing button at the top of the Camera Raw window and draw a selection over any lens spots. Reposition the healing source for best results. Voila - instant spot healing.
8: Paint directly onto 3D models
CS4 Extended now enables you to paint directly onto 3D textures whilst viewing them in situ. First, select the material you want to edit from the 3D panel, then use standard Photoshop brushes to paint onto the 3D surface, previewing your changes as you make them. You can also edit Lighting and Rendering modes. To keep Photoshop responsive, keep rendering to low quality until you're ready to output.
9: Use workspaces for productivity
Photoshop (and all CS4 applications) now use an improved workspace system. Workspaces are saved the way you left them, so switch between workspaces from the convenient button located in the top right of the application and get all the panels you need in an instant. Set up fresh workspaces for different types of work so that you always have the correct panels available when you need them.
10: Organise your windows quickly
Using Photoshop's new support for OpenGL, you can stack up your open windows in lots of different arrangements. Click on the Arrange Documents button in the toolbar and select from the presets to arrange your images in tiles, as a series of tabs, two-up, three-up or free floating. You can adjust zoom and position in all documents simultaneously from the same menu.
11: Rotate your view
Looking at your artwork upside down can quickly alert you to things you didn't notice viewing it the right way up. Rotating your canvas used to be a slow and arduous process on large images, but with OpenGL support you can quickly rotate your view to get full context. Choose the Rotate View tool from the toolbar then click and drag. Remember that you're only changing your view of the canvas - the artwork itself remains the same, you just have a different view of it.
12: The Sponge tool is safe to use!
At last the Sponge tool is almost fail-proof. When you're using the newly improved Dodge and Burn tools, a side effect is that the areas you work on will either be de-saturated or more saturated, depending on whether you Burn or Dodge. Use the Sponge tool set to either 'saturate' or 'desaturate' as necessary to repair any unwanted effects.
13: Vignette-free Photomerge
Photoshop now removes vignetting from photos within a Photomerge, which cuts down editing time dramatically. Select a series of images in Bridge and choose Tools>Photoshop>Photomerge. Accept the default options for each step and Photoshop will quickly assemble your images into one large, seamless image with any vignettes automatically removed.
14: Restore missing functionality
Adobe removed some older functionality from CS4 as part of a planned architecture migration. If you really can't manage without support for TWAIN on a Mac, the Extract and PatternMaker filters or the Web Contact Sheet batch, you can download the missing plug-ins and filters in a convenient package directly from Adobe, for Mac and PC.
15: Make it your own
Photoshop is now more extensible than ever. Download Adobe Configurator and you can quickly gather together favourite operations, filters or scripts into your own custom panel. You can save and distribute your panels to other members of your design team or across the web in order to facilitate easy access to commonly used or essential tools.