FX Photo Studio HD

FX Photo Studio HD contains an astonishing 187 filter effects, in a large number of categories. Art includes pencil sketches and brushstrokes; Color Fantasy produces strong, contrasted and tinted results; Cross Processed creates tinted channel mixing operations; and so on. Further categories include Textures, TiltShift, Glow and Grunge, among others. The app can also simulate X-Ray and night vision, lo-fi camera styles, and much more.

Each effect has a maximum of two sliders for the user to tweak the settings, usually covering brightness and contrast. Once an effect has been applied, it's possible to add further effects on top to produce complex image enhancements. Users can mark effects as favourites, and can add presets that combine multiple filters. Further sets of effects — frames, lens effects and spot colour adjustments — are available through 59p In-App Purchases.

Although it's geared mainly towards fun filters, the app does include a small range of traditional image correction tools in the form of Brightness, Contrast, Saturation and Gamma. But with just a single slider each, these are something of an afterthought. It doesn't come close to a dedicated retouching app such as Filterstorm.

The problem with this app is that there just isn't enough user control. You can reflect a picture horizontally or vertically, but can't set either the position of the reflection or which side gets reflected. While this is eased by the inclusion of a basic set of tools — Crop, Rotate (which can also flip horizontally and vertically) and Resize — it's still cumbersome. When using the special effect filters, it would be useful to be able to set the colours used for tinting, or the size (rather than just the amount) of applied textures.

The effects in FX Photo Studio HD are identical to those in the £;1.19 iPhone/iPod touch version, but the larger screen of the iPad means we have a much better view of the result of each filter.