Ok, so did sort-of the inverse of the project, but I think this looks better than the other way around of color-splashing. I especially like the color of the rocks - I didn't even edit the color, they're really that bright!
This project wasn't too difficult to make. Here were my steps:
- Selection tool (magic wand) > selected the fish
- Split layers
- While still selecting the fish layer, colors > grayscale
- There you go!
This is as verbatim as I can fully remember (is that even english?), photoshop might have some different steps I missed along the way, but for the most part this was fairly simple.