A new trick.

[Erik]

The image speaks for itself, except that I applied the FindEdges filter to the upper image (which is a copy of the background layer)
Enjoy

 

[vogonpoet]

Erik: you always speak in riddles?

The image is great, but I don't understand what the trick is?

~waits for clarification, whilst feeling somewhat obtuse~

 

[Erik]

In the line of the research project I am working on, I combined an image with itself in greyscale as mask to make the dark parts transparant and keep the white ones more the original colour.
Further tweaking on that mask offered such a vista of possibilities that I decided to share it. If you don'tt mind, off course... B7