Frequency Separation vrs Lab Lightness channel

[philbach]

I was wondering whether you can similar results to frequency separation by working in Lab Mode on the Lightness Channel on a given photo.

[Der_W]

I think you're confusing two issues here :-).

Frequency separation is used to work on different levels of spatial frequency at a time, e.g. grunge and detail.

The Lightness channel of LAB on the other hand is used to work on luminosity alone instead of working on color and luminosity simultaneously like you would in RGB (if you're not setting the mode to "Luminosity").

A derivative of the frequency separation technique could be used though, in which you'll just desaturate the bottom layer and use Apply Image to find the difference on the top layer.
But then again, why not simply use "Luminosity" mode?

[philbach]

Thanks, Jonas.

[Chain]

^Jonas agrees with Jonas on this one.