Curves (or Levels) and the "L" Channel in Elements 2.0

[Patrick Cox]

Hi,
Is it possible to edit the "Lightness" channel in Elements 2.0? If so, any assistance on how would be appreciated! I have installed Richard's hidden power tools and have been reading his book for about a week. I know I can Split Luminosity and then layer a curves adjustment (or levels for that matter) on top, but I am not sure if this is adjusting only the "L" channel. How would I know if the adjustment layer is impacting only the "L" channel vs the entire image, including colors?

Thanks a bunch!

Patrick

[Gary Richardson]

Hi Patrick, the Lightness Channel is only available if your image is in LAB mode, as far as I'm aware. This is not available in Elements 2 as shipped.

[Richard_Lynch]

Lightness, hopefully it is explained in the book, is almost exactly what you have in the L channel of Lab. You don't necessarily need to be in Lab mode to manipulate the lightness, except in a purist sense. The L channel is just another image component that can be extracted by other means (in this case filtering). Just like you can extract the C, M, Y, and K components from an RGB image, you extract what is, in essence, LAB's L, and make changes to tone distinct from color.

There isn't an L or Lab mode in Elements as shipped, no...but why should that stop you?

[Gary Richardson]

Sorry Richard, I haven't read your book and told it as I saw it. I'm happy to be proved wrong, and glad you can help Patrick. Any chance of explaining how this is done by filtering, or must I buy your book to find out.

[Patrick Cox]

Richard,
Thanks for your reply. I do own your book and cd but I still am not sure how to edit the L channel. I know how to split or add luminosity using your power tools. I also know how to add a levels or curves adjustment layer. But I am not sure how I know if I am only applying the levels or curves adjustments to L channel, rather than the full RGB. (I hope I stated this correctly.) This is where I need some assistance.

Thanks!

[Richard_Lynch]

Well, the result is enabled by tools I include with the book. The mechanism is something that isn't quite available without the tools (it isn't really just desaturating or other simple calculated results, and it isn't a light process filtering like most of CMYK or RGB). At least it isn't done that way in the simple process I use now. it could be something I have to revisit in the future as content in Elements changes.

I don't hide technique in the book....most Photoshop users would learn a thing or two with the book...that's why I wrote the Hidden Power of PS CS.

[Richard_Lynch]

Patrick,

Easy answer: when you make the Luminosity/Color separation, group the changes you want to make to the L channel to the Luminosity channnel. Just stack them above and press Command/CTRL+G.

OK?