Luminosity masks

[skwerlmasta]

Hey guys,
First post. I'm relatively new at photoshop and I have a question about luminosity masking. I've gotten pretty proficient with creating the masks but I've run into a problem that I can't quite figure out.
I use photoshop mainly for photo editing and retouching.
I've created the luminosity channels, 6 iterations each of brights, darks, and mids.
My question is this:
I would like to subtract the 6th channel, which contains only the extreme darks, from what is on the third channel, which contains a broader selection of darks.
I'm pretty sure there is a key, or keys, that I have to hold down to make the selction, but for the life of me, I can't figure it out.
Any help would be appreciated.
Thanks

 

[IamSam]

Sorry.............I didn't read, you want to subtract one channel (selection) from another...........hold on.

 

[IamSam]

This could take awhile, it's not as simple as I thought it would be. But I think it can be done.

 

[IamSam]

These are the additional channels that are created when I run a Luminosity Mask action.......



I have

bright 1 thru 6

dark 1 thru 6

midtone 1 thru 6



I'm not sure what your trying to do since there are 3 #6 channels and 3 #3 channels.

Are you saying want to select the dark 6 channel from one of the 3 #3 channels?

 

[skwerlmasta]

OK, this is as I understand it. I'm still trying to figure it all out. But my channels look identical to yours. The dark #6 channel contains only the darkest tones. The dark #3 channel, I believe contains a larger amount of dark tones. Those darks include what's in the #6 channel. I would like to select the #3 channel without the extreme darks in the #6 channel. If that makes any sense at all.
I really do appreciate the time and effort that you've already taken here.
Thanks
Nevermind, I think I just got it. I think I have to command click the number 3 channel and then command-alt-click the number 6 channel.
I believe this is correct. Some button mashing to figure that one out. Thanks for the input though. Your first response got me there. I just had to figure the rest out.

 

[IamSam]

I think I have to command click the number 3 channel and then command-alt-click the number 6 channel.
I believe this is correct.

This would be correct.

You can also use layer masking. Produces the same effect and offers better editing option if needed.
Hide all mask for channel 3
Reveal all mask for channel 6