Luminance Masks

[Orbster]

Evening all, I have followed this tute and I'm having problems following it exactly.

When I try and apply a channel to an adjustment of my choosing, I get a red mask across the whole image and the

alteration is global as opposed to the selection of the mask if that makes any sense?


http://www.youtube.com/watch?v=kP4r1o7RWVY

Any ideas/pointers?

Thanks guys and girls.

 

[Tom Mann]

You can't use the channel directly as a mask without side effects like you observed. The better approach is to first duplicate the selected channel, give it some meaningful name like "blue ch mask", and then use the duplicate as a layer mask, or for whatever other purposes you like.

HTH,

Tom

 

[Tom Mann]

I should also point out that like most things in Photoshop, there are always alternative approaches. For example, if you want to use the blue channel as a luminosity mask for, say, some adjustment layer, a shortcut is to put the layer in place on the stack (but have it do nothing), then cntrl-click on the blue channel. This will give you a selection. Then, select the adjustment layer and click on the little new layer mask icon at the bottom of the list of layers. This will give you the same result as duplicating the blue channel and going that route.

Gotta run,

Tom

 

[Orbster]

You can't use the channel directly as a mask without side effects like you observed. The better approach is to first duplicate the selected channel, give it some meaningful name like "blue ch mask", and then use the duplicate as a layer mask, or for whatever other purposes you like.

HTH,

Tom

This is what I've been attempting to do but I seem to be unable to use the duplicate mask in conjunction with an adjustment layer.

Have you seen the video link?

 

[Tom Mann]

Sorry, but I have neither the inclination or time to sit around and watch some one else's tutorial and follow along / critique / annotate it, but I'll be happy to try to help you directly.

First, when you are viewing the channel palette, immediately after you made the duplicate, you need to turn off the original channel, and then turn on and select the new duplicate channel that you just made. Turn on and off layers by using the "eye" icons. Select a channel by clicking anywhere in the box that represents it, other than where there is text or on the "eye" icon.

Next, control-click somewhere in the box for the new duplicate channel, but, like before, be sure to cntrl-click where there is no text, and not over the eye (aka, "visibility") symbol.

This should have turned on a "marching ants" display of the areas you just selected. If you can't get to this point, stop and let me know.

Assuming you have the "marching ants" display, click on the tab for the "Layers" palette to bring it to the front.

Select the adjustment layer that you want to mask by clicking on it (again, not its "eye" icon). Make sure it turns blue to show that it has been selected.

Go to the very bottom of the layers palette and click on the "add layer mask" icon. It's the little rectangle with the hole in it -- usually the 3rd from the left.

You should now see a layer mask icon appear next to the icon for the adjustment layer in the layers palette.

Your adjustment will now be confined to the selected areas.

HTH,

Tom M

 

[Orbster]

Thanks for your help Tom, much obliged

 

[Tom Mann]

You're very welcome.

Did the last set of directions help? Were you able to get it to work?

T

 

[Orbster]

To a point, yes.

I've obtained a set of actions that generate all the required masks along with the curves layer and this will help me no end.

A bit frustrating to do it this way as I like to be able to pick things apart and do it myself rather than rely on auto actions but there you go.

I got them from this fine chap Thomas Shue, here's his blog...

http://lilsamedia.com/blog/wordpress/2012/08/08/luminosity-masks-serious-control-in-post/