BlowUp review

Enlarging image files without losing quality is the holy grail of photo processing.

But since we already have the choice of both pxl SmartScale and Genuine Fractals, both from OnOne Software, is there room in the market for yet another enlargement tool?

A few factors mark BlowUp out: first, it can scale RGB, greyscale and CMYK images - to print CMYK in Genuine Fractals, you'll need to pay an extra £50 for the Print Pro version. And secondly, BlowUp has the ability to upscale layered Photoshop files without the need for flattening - a useful capability when you find that the image you've been working on is smaller than the client needs.

As with all Alien Skin software, the interface is clean and straightforward. BlowUp is an automation process, rather than a filter, so it's launched from Photoshop's File > Automate menu. The window shows the original image and an enlarged portion of it in separate panes, together with simple text fields for entering the width and height required for the new image. If you prefer, you can choose to scale by percent or by resolution instead.

Three further controls offer useful functionality. A Sharpen slider compensates for the inevitable edge softening and an Add Grain slider brings back lost picture grain - which usefully gives the illusion of extra detail by covering over-smooth areas, a feature photographers will value highly. There's also a handy Duplicate Image Before Resizing button, so you don't lose your original.

The quality of the enlargements is certainly vastly superior to the built in Photoshop resizing option, producing none of the pixellation and fringing we're used to. Enlargements up to 1600% can be remarkably good and adding some sharpening helps the process.

In practice, the quality does depend on the nature of the original image. Landscapes tend to work particularly well and very graphic images, such as logos, benefit enormously from the process, as they'll enlarge to enormous sizes with no visible pixellation or blurring.

The images that are least successful are those of people; portraits tend to become smoothed out. This is inevitable, due to the impossibility of recovering skin texture from a small image. Enlargements of Googled images are significantly better, although they become more graphic and stylized than we'd like.

Overall, Blow Up is a good solution to an impossible problem, but don't expect miracles.