How can I "layer" blending modes?

[juliewood]

Sometimes I want to "layer" blending modes, most commonly luminosity and lighten (so that the layer only affects the luminosity and not the color, but ALSO only affects the darker tones.) Obviously, I can't set 2 blending modes at once. I tried putting the layer into a group and changing the group from Passthrough, but the group blend mode seems to override the layer blend mode entirely. (ie a lighten layer with a luminosity group now acts like I had simply set the layer to luminosity, or a luminosity layer with a lighten group acts like the layer was set to lighten.)

Is there an option somewhere on the layer or the group where it will enhance rather than override it, or some other way y'all can think of to achieve the same effect?

Thank you!

[Nasturtium]

you can get a similar effect by putting a copying the green channel on top of your layers and changing the blending mode to 'lighten'. this will lighten your whole image.

to stack blending modes you can use 'apply' image (apply the first blending mode to your layer to make it permanent...) then change the layer's blending mode to the second blending mode...

I do this a lot; I made a blank layer on top of my layer stack. (this works pretty good for layer effects too) then I stamp a flattened copy (Shift+Alt+CMD) of the visible layers...this will pick up the first blending mode. Now you can change the blending mode of the flattened layer to a different mode...

HTH - Nancy

[ratpat13]

You are right that changing a groups blend mode overrides the blend modes of the layer within. SO if you are trying to achieve a luminosity and lighten affect only in the light areas of the image, my first thought is could you achieve the same degree of lightening using a cure or levels adjustment as you would with the lighten blend mode, that way you could lighten the image (with curves) isolate it to just the light parts of the image and then change the blend mode to luminosity so you wont change color.

If you can't isolate the tonal range enough just with curves you could use the "blend if" slider inside of "Layer Styles" to refine the tonal area your adjustment affects. You could also use a luminosity mask applied to the adjustment layer to refine the area affected by your change.

If you still just want to use blend modes you could use Nasturtiums suggestion of apply one blend mode, merge visible on a new layer (delete the layer with the blend mode applied) and then apply the luminosity or lighten blend mode to the merged layer.

You could also put both layers, the one with the lighten blend mode and the one with luminosity blend mode in a group and use blend if on the group.

[Der_W]

What you can easily do is create a new adj. layer of whatever kind you like (I usually use "Brightness/Contrast" because I don't have another use for it), set its blending mode to "Lighten", clip your "Luminosity" layer to it and have fun .
Or if you want to work with groups, you need a base layer in "Normal" mode, so put a copy of the background layer at the bottom of the group, blend your next layer with "Luminosity" and set the group's mode to "Lighten".
I'd prefer the first way as it's more flexible and lightweight, but you can of course chose whatever you like best !

[juliewood]

Thank you all so much for the feedback - I think I wasn't clear enough though. I'm not trying to actually lighten the image, but to do something like run a dust&scratches filter on a layer, set it to not affect colors, and also have it only apply in places where there were darker dust spots. I will try the different suggestions and let y'all know what works best, thank you!

[unimatrix001]

Just a thought if you are looking to separate the layers lightness and color you could try the LAB mode it divides the image into three layers. lightness and two color channels making adjustments to the lightness channel does not affect the color channels. you could make all your adjustments to the lightness channel and then convert back to rgb mode to make your final corrections.

[mushmush]

Hello Julie- I would just duplicate the layer and change that new layer's blending mode to whatever you want: 1 layer set to Luminosity and 1 set to Color for example

[Chain]

Some good suggestions, some not so good.
What nobody has remembered is that you can use a (luminosity) mask to limit a layer to the light/dark tones of the image (load the RGB-channel as a selection then turn it into a mask, edit the mask using curves/levels), or you can use the "blend if" sliders in the layer blending options.

Now that you have made it clearer with a good example of what you want to achieve, it will be better to give a more targeted answer.

If you want your "dust & scratches" (or any other) filter to only affect luminosity, and also use a blending mode to set it to only affect light or dark tones there are many ways of doing it. The quick way that I probably would have done:
1. Merge a copy of your image onto a new layer.
2. (Optional: turn it into a Smart Object)
3. Run filter on this layer.
4. Edit > Fade... (or if it's a smart object, choose to edit the smart filter blending options in the layer panel) and set it to Luminosity.
5. Option 1: Blend the layer normally using lighten/darken/darker color/lighter color/whatever.
5. Option 2: Edit the Layer Blending options and adjust the Blend If-sliders so it only affects the brightness range you want.
5. Option 3: Load selection from the RGB-channel (luminosity). Add a layer mask (from the selection). Use Curves (ctrl/cmd-m) to alter the luminosity mask until it affects the image the way you want.