Image Editing Tutorial - Selective Monochrome
Once you're happy with your selection, actually removing the colour from the rest of the picture is the easy part. First we've currently got the flowers selected, so we need to invert the selection so that it's just the background that's selected. In the Select menu (Selections in PSP) simply select Inverse, or use the keyboard short-cut Ctrl+Shift+I.
Most of the advanced editing programs now support adjustment layers, and this is the best way to make any gross changes to an image, since it's non-destructive and can be easily reversed. We'll use a Hue/Saturation layer to simply reduce the saturation to zero, draining all colour from the selected area. There are other ways of doing the same thing, but this method produces the desired result and works in pretty much any editing program.
As an additional step, just to make the colours look a bit brighter, I've also tweaked the levels on this image, slightly compressing the tonal range of the black and white area using the output sliders to remove dark shadows and bright highlights. This makes the background look a bit faded and dull, and the flowers really stand out in comparison.
When you're done, cancel the selection and save the modified image under a new file name to preserve your original photo.
This technique works well with anything in which the colour of an object is its main feature. A monochrome portrait with just the eye pupils retaining their colour, a child's brightly-coloured toy in a bleak grey world, or a butterfly against black and white flowers could all look good, just to give you some ideas. Go and play with the effect and see for yourself what works.
