Corel's KPT Collection is possibly the most famous of Photoshop software plug-ins. Originally developed by Kai Krause and published by the now defunct MetaCreations, this set has become a favourite among digital artists.

The new KPT Collection includes filters from KPT 5, 6 and KPT Effects, and the 24-strong set really is great value. Anyone fascinated by Photoshop will recognise such favourites as KPT Goo and Noize. Goo is pretty much what you'd expect, if somewhat pointless - enabling you to splodge translucent goo on top of your images. Noize is a fun filter that enables you to overlay your images with random cloud-like noise.

To get the best from KPT filters, you should treat most of them as effect generators rather than filters. Use FiberOptix on a layer above your image with a Multiply Blending mode, for instance, and you can produce stunning effects. KPT Collection is all about experimentation.

Indeed, you'll have most fun with KPT when you're tweaking with no specific goal in mind - results are interesting and varied, and often you stumble across a striking effect purely by accident. Fluid is a great example; it turns your image into a pool of liquid, which you distort as you see fit. It's similar to Photoshop's Liquify tool, but more fun. Another favourite of ours is RadWarp, which enables you to interactively apply a radial warp to your image.

Newcomers to KPT will appreciate the filters' superb engineering. The only thing that stops this package getting five stars is the lack of an upgrade path from earlier versions - with this, KPT Collection would no doubt become one of the bestselling filter sets of all time. Mark Sparrow