From: Daniel Piechnick
Remote Name: 126.96.36.199
Hi TD. What you want to do here is to isolate the flower, as you did before. (A good method for doing this can be found in my "Separation" tutorial.) Then press Ctrl+U, and reduce the Saturation. This will remove all colour from the layer, leaving it with greys only. In this window, there is also a little drop-down box, which allows you to select a colour group (like "Reds"). While using this, it only alters the colours you have selected (so only reddish-colours would be altered for example). If your background has a distinct colour (or colours), you can use this option, so you can desaturate the background without even having to cut the flower out.