Aquarelle is an image processing/enhancement application for iPhone. It is the sibling project of another graphic processing app called iLensFX.

Aquarelle is aimed at processing high resolution still photos as opposed to iLensFX which processes the real time video camera stream.

Aquarelle adds a few more filters on top of the ones found in iLensFX and currently offers 39 base filters all of them being highly configurable which gives you a much wider range of filters than the 39 base filters.

Aquarelle has :
- 10 distorsion base filters : Grid Warp, Pinch, Glassify, Diffuse, Granite, Swim, Ripple, Water, Magnify and Kaleidoscope. Pinch filter for example can do Twirl and Pinch&Twirl combined.

- 12 styling base filters : Edge Detection, Burst, Contour, Emboss, Smear, Oil, Decay, Halftone, Dissolve, Add Noise, Mosaic, Sparkle.

- 13 coloring base filters : Solarize, Posterize, Invert, Grayscale, B&W, Adjust Levels, Adjust RGB, Adjust HSB, Gamma, Contrast, Exposure, Gain, Rescale

- 4 texture base filters : Caustics, Wood, Marble, Metal.

You can lay filters anywhere on the picture, you can lay them over each other at the position you want and the size you want.

Aquarelle allows you to fully configure each filter where there is something to configure.

Aquarelle does not have filters like Sepia or that kind of filters because these are in fact a composition of other filters which you can easily achieve with Aquarelle and you are not limited to a set of colour tints but you have access to the entire RGB or HSB colour palette by using HSB and RGB filters together with Grayscale, for example.
Another example is achieving Sketch filter simply by playing with the Emboss filter setup.

Aquarelle is very simple to use, straightforward and does the job, no bluff no resource waste with unneeded fancy UIs. You'll always see/work on the whole screen.