Greytinter

The xero : greytinter filter can give some very tasteful 'artistic' effects. The filter reduces the image to greyscale, but allows the original colour to be added back in to give subtle tints. The end result can look quite impressive...

The filter has four sliders; the 'Overall tint' slider takes the image from greyscale at the extreme left, to full colour at the right. The other three sliders are cut/boost controls for red, green and blue, but they don't work on their respective channels as one might expect. Each slider tries to identify regions of the corresponding colour in the image, and then boost or cut the colour of those regions. In other words, the idea is to change selected colours in the picture rather than any overall colouring of the image as a whole.
It's those d*mn kids again! Here's Lee and Jack, walking on Cadbury Hill near where we live. It isn't a great photograph; it's more of a quick snapshot to record the moment. We'll never turn it into a piece of great art, but we can at least make it more interesting.
I've left the overall tint at monochrome, but set the rest boost toward full so that the skin tones and the logo on Lee's shirt come up to almost full colour. As a bonus, the earth of the track we were following up the hillside colours up too, giving a nice perspective to the picture. As an afterthought, I gave the blue a little boost too so that the sky would balance the composition better.
The filter isn't quite capable of creating a little girl in a red coat set in a monochrome landscape, but can give some very nice effects nonetheless.
In this picture, I've left just the tiniest tint in the background, but boosted the red to bring out the boys. I then actually cut the blue channel, which gives a strange brooding colouration to the sky; it has also affected Jack's boots, and the bright-blue railing behind the boys. The rock seat on which they're sitting is carved from a reddish stone, so that has more or less kept its colour.