Conventional wisdom holds that editing an image in Photoshop is best done in an RGB (red-green-blue) or CMYK (cyan-yellow-magenta-black) colorspace. About the only thing most people attempt to do in L*a*b* is sharpen the L* (luminosity) channel, which preserves color balance while sharpening.

Digital imaging contrarian Dan Margulis has just written a book showing how to edit in Photoshop’s LAB Color mode. (You can read a couple of chapters in PDF from his site.)

Margulis can be a controversial guy. At one point he said color management is the “worship of certainty.”