Photoshop CS3 had a special Extended edition which included the ability to work directly with 3D and video content, and this ability is expanded in CS4 Extended. In this enhanced version of the program it is possible to paint textures directly onto 3D models in Photoshop, and 2D layers can be converted to 3D layer that can be re-sized and rotated in three dimensions. This 3D integration probably won't be much use to the average home user, for whom the standard version of the program will be more than sufficient, but to those working in 3D animation it means that textures and shading can be created and edited without having to constantly export and import files between different programs. The same applies to video content, which can also be imported and manipulated directly in CS4 Extended, with limited timeline editing functions and video rendering.
Photoshop CS4 Extended also has a number of other features useful to professionals working in graphics production, as well as in specialist scientific and forensic fields, such as an enhanced counting tool and the ability to share work over networks.
Any review of Photoshop would be incomplete without also taking a look at Adobe Bridge, the file browser and organiser that is installed along with Photoshop. Bridge too has received a substantial upgrade, and has a number of new and useful features.
Changes to the interface include the addition of Forward and Backward buttons like a web browser, a full file path bar so you always know what it is you're looking at, and a number of pre-set workspace layouts. Search functions have been improved, with the addition of a search bar and improved keyword system. Bridge can now export Web galleries, including some pretty sophisticated Flash-based slideshows, ideal for uploading direct to a gallery website. It can also export PDF contact sheets, and import images direct from a camera. Any image can now be opened in Camera Raw, to take advantage of its advanced exposure and tone controls.
Photoshop CS4 is also closely integrated with Adobe Lightroom 2, the professional Raw file processor, image organiser and photo editor. See our review of that product for more information.
Version CS4 is the most complete upgrade of Adobe Photoshop since the launch of the original CS version in 2003. If you have avoided buying CS3 because it was not enough of an improvement on CS2, then now is definitely the time to upgrade. It goes without saying that it is the most powerful, the most comprehensively complete and the highest quality graphics editor on the market, but CS4 really does add so many new features, and so many improvements to existing tools, that it is an essential purchase for any professional, and an aspiration for most amateurs. It's expensive, and annoyingly significantly more expensive in the UK than in America, but if you want the very best you have to pay the price.