Color/Luminosity separation

Started 3 months ago | Discussions thread
OP Currantos Senior Member • Posts: 1,448
Aim

Joachim B wrote:

Currantos wrote:

gordonpritchard wrote:

Why not change to Lab mode then copy the L channel to a new document make your edits then copy that and paste back into the L channel of your original image?

somehow I was not able to do that.

It's like LAB locks you out.

Do you have a way to do that?

I copies the image to new file. Converted to LAB there. Went to channels, copied the luminosity.

But then when I tried pasting anywhere it won't let and same in reverse, it won't accept backward.

Would be nice to try

That's because you are trying to copy Lab information to an RGB document. Doesn't work that way. You would have to convert to Lab, make the edits you want in there, and then convert the result back to RGB. Then you can copy.

So still my question: what kind of edit would you like to do, so we can see if there is an easier workaround. Describe the result you would like to get, not the proces that you think will get you there.

Here is what I am trying to get.

Take a portrait or another image with a face well seen. Apply Clarity +100 slider. Or alternatively a HiRadius LowValue Unsharp mask strong contrast. The colors will shift dramatically and the person will look 'baked in an oven". Horrible.

Now do that just to the luminosity component leaving colors intact? You get a very strong contrast image where lighting looks dramatic/impactful. It is not always possible to get lighting right in camera due to a variety of reasons. Would be enhance it up with post production.

I've converted the image to black and white and done it and it looks so much better, the dramatic strong contrast really stands out. Now it's just a matter of keeping colors reasonable while applying to the "b/w luminosity" component.

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