Adobe Photoshop CS

Another major advance that will be appreciated by all professional users is Photoshop's hugely expanded colour support for images with 16-bits per channel rather than the usual 8-bits. This has now been extended to include painting, text, shapes, styles, more filters and, most importantly, layers. Having a wider range of pixel values to work with results in richer and deeper colour all round, especially when it comes to highlights and shadows, and helps avoid undesirable posterization. And just to rub in the superiority of its number-crunching engine, Photoshop CS has massively increased the size of the images it can handle to a whopping 300,000 pixels x 300,000 pixels with up to 56 channels per file.

Once you've loaded your images into Photoshop, the most common requirement is to enhance them and here Photoshop CS adds a number of useful new features. To begin with, it provides a new Histograms palette. This shows you live histograms of the current image and can be set to show both composite and individual channels so that you can see exactly how the pixel values are distributed in your image. Most usefully, when you're colour correcting, the palette shows both before and after histograms so that you can see exactly how your adjustments will affect the colour values (it also highlights the benefits of the new 16-bit handling).

Photoshop CS also adds three new colour correction options under the Image Adjustments menu. The first, Highlight/Shadows, lets you quickly restore detail lost in over and under-exposed areas of an image without affecting the overall colour balance. This is no more powerful than the existing Curves command but the basic control is a lot simpler. The second, Photo Filter, which is also available as an adjustment layer, is designed to simulate traditional camera-based filters to warm or cool the image or to strengthen particular colours.

Adobe is pitching the third new adjustment effect, Match Colour, as one of CS's killer features, just as image healing was for version 7. Essentially it takes an image and applies its colour to another image or image area. This can be used to create eye-catching effects, but its main use is to create seamless compositions from images that were shot under different lighting conditions. Rather less exciting, but probably more regularly useful, is the new Colour Replacement tool which lets you paint colour onto the image while retaining the underlying texture and shading.

If you want to get a bit more creative with your images it's time to turn to Photoshop's Filters menu. This provides a new Lens Blur option, which enables highlights in an image to take on the shape of a simulated lens aperture, but what really makes the difference is the complete reworking of the way in which all filters are applied. In the past each effect was a standalone affair with its own awkward dialog, but now you can access and control all filters from the new central Filter Gallery. This single dialog provides thumbnail previews of all available effects. Select one and you can change its parameters to the right while seeing the effect on the large resizeable preview pane to the left. Even better, the centralized control means that you can apply more than one filter at a time and customize all parameters to get exactly the effect you want - though strangely there doesn't seem to be an option to save and load filter stacks.

The Filter Gallery is a massive improvement, especially given the creative freedom Adobe has managed to graft on to Photoshop CS's layer handling capabilities. To begin with, Photoshop CS extends the idea of layer sets by allowing them to be nested up to five deep - absolutely essential for managing layered units of a composition such as navigation bars that comprise multiple button and text layers (these nested sets are also recognized when a PSD is imported into Illustrator).