ColorClaw from developer GreenParrotPictures is a very clever photo colour manipulation app for the iPhone, that allows to remove the effects of artificial lighting/colour casts or add/enhance colour effects to your iPhone photos.

The apps interface

ColorClaw has two different styled user interfaces (UI). A standard, if slightly cartoonish looking one, and a "Pro Look UI" which can be turned on or off via the iPhone's settings menu (not from within the app irself). Because of this I am going to break the review in two, the standard UI and the Pro UI.

First lets look at the standard interface

Launch the app and you will be presented with the first of three screens with instructions on what you need to do to get started. At this first screen you are instructed to tap the current photo to select a new photo from the Camera Roll/Photo Albums.

When you've selected and loaded your photo you then tap the arrow which takes you to step 2, where again you are instructed to select another photo, and It is here that the clever stuff begins.

At this second screen you can select and apply to your photo what ever colour effect you like, using another photo to provide the base effect. This is done by selecting either predefined photos from the apps "Color Claw Colorings", like....

• Carnival
• Green Parrot
• Blue Haze
• Sepia Hue
• Urban
• Tribal

....or from your own photos allowing you to customise the colour effect.

This process is quite difficult to explain without showing it on video (something I had considered doing), but essentially if you have a colour style that you want to achieve, whether it be vibrant colours (Carnival) or neutral tones, then selecting a corresponding photo from either the "Color Claw Colorings" or your own "Photo Album" makes this all possible.

Once you have selected either a photo from the "Color Claw Colorings" or from your "Photo Album" you are taken to the final step and the image is processed, and it is here you can either double tap the screen to save your finished photo, or tweak the brightness and strength of effect using the 2 sliders at the bottom of the screen, and then tapping to save.

If you decide that the end result is not what you are looking for, or you want to select a different photo to edit, you have to tap either the 1st or 2nd step photos, which due to the fact that these are overlapping one another can at first be a bit difficult.

Once you have finished tweaking your photo, simply double tap your photo and it is saved to the Camera Roll.

Now lets look at the "Pro Look UI"

Right, that's the default interface and process out the way, so lets look at the "Pro Look UI", which as mentioned is activated/deactivated via the iPhone's settings menu. In addition to turning on/off the "Pro Look UI", you can also enable "Show Whole Photo" from the iPhone's settings menu, which allows you to see your entire photo when tweaking.

Having switched to pro mode, this time when you launch the app the interface looks completely different, having lost that cartoon look and feel (although to be honest I like the standard UI). The first thing you will notice is the screen now contains 3 boxes, 2 small boxes in the top section of the screen and 1 large box in the lower part, and a slider at the very bottom, if viewed in portrait mode. Now if you prefer to work in landscape mode, then you will have the 2 smaller boxes stacked to your left and the larger box to the right, with the slider still at the very bottom.

In the view above you can see the yellow lines on the original photo (top left) caused a blue cast on the tarmac road, however by selecting and applying a neutral coloured photo from my "Photo Album" (bottom left), the colour cast has been removed.To use the app in this mode you simply tap the large box, open your "Photo Album", select a photo to tweak, which will then load to the large box. Once loaded simply drag the photo from the large box to the box that says "Your Photo", and then follow the same process to select the photo you are going to use as the base for your colour effect, but this time drag the photo to the box that says "Coloring Photo". Once you have done this you will see a message saying "Processing" and after a few seconds your corrected/tweaked photo will appear. Now if the app over or under does the effect, not all is lost, as you can use the slider at the bottom to make adjustments to the colour effect and/or the brightness, and tapping the slider toggles between the colour effect and brightness options.

If at any time you want to change the photo to be edited, or the photo that forms the basis of your colour effect, it is a simple case of dragging which ever photo you want to change back to the large box and selecting a new photo from either the "Photo Album" or "Color Claw Colorings".

Once you have finished tweaking your photo, simply double tap the large/main box and your photo is saved to the Camera Roll.

Above: Original photoAbove: Original photo given the "Urban" effectAbove: Original photo given the "Sepia Hue" effectAbove: Original photo given the "Custom" effect using one of my own photosSo what do I think of ColorClaw?

In a word "fantastic", this has to be one of the best photo apps I've reviewed in a long time, and I really like the way it cleverly analyses the photos used in the process, and then applies them to your iPhone photos. Like all photo apps ColorClaw isn't fool proof and doesn't always produce the results you'd expect, but with a bit of experimenting you can achieve some unexpected and unique results, and so deserves 4 stars out of 5.

AppStore Link: ColorClaw - Price £1.79/$2.99

Update from Green Parrot Pictures: Version 1.1 saves at native 3GS resolution. It has been submitted to the App store, so hopefully it will be available within the next week or so.

A couple of tips for users:
To go back a step in the default UI, you can drag the frame off the screen - press and hold the label at the bottom of the photo and push the photo off the screen.

If you do this on the first step, it swaps your photo with the coloring photo. You can also swap the images in the "Pro Look" UI - just drag the photo across.