I'm glad you like my image. I already have several "selective colouring"-images in my gallery like

my friends cat http://www.renderosity.com/mod/gallery/index.php?image_id=1407064&member

and one of my personal all time favorites http://www.renderosity.com/mod/gallery/index.php?image_id=1026965&member

but doing this was somehow different because the two images (b/w and colour) blend into one...