Help with Understanding Masks Please

[nebgranny]

I was finally able to do Vikki's Mask tutorial and what fun it was to see it work. BUT..I just do not get this mask thing.

It just does not make sense to me...We put a completely BLACK mask over an image covering it ,then we use white to paint over what we want to cover up?? It would make sense to me that if we paint over the black with the white it would crack open up the black mask and it would SHOW the marks and things under the mask.. NOT HIDE THEM !!???

My mind just does not comprehend this concept...If we put black over an image it will be covered , how then by using white to paint over the bad spots on say the face to cover the spots, can we then be covering up or changing it to a good spot when it is all covered with black?

I know my stupidity is showing here but just do not understand how this works. Can someone humor me and try and explain what I am or am not "SEEING" Punn intended..LOL Thanks Nebgranny

[Gary Richardson]

Hi Neb, I think you're getting a little confused here. When you paint white onto a mask, you are revealing the adjustment.

Firstly using Vicky's method you copy your base layer.
Then you apply an adjustment to that layer. To that layer you apply a cover all mask (a black mask), therefore none of the adjustment will show through.
Lastly, you paint white in the areas that you wish the adjustment to appear.

So black is covering the layer, therefore no effect (it is masked), and you can only see the base layer.

White, reveals the effect (it is unmasked), therefore you see the base layer and also the adjustments in the areas you have painted.

Hope this clarifies things a little.

[cardmnal]

neb,

Think of the mask as a projector and the layers beneath it as a movie screen. when you fill the mask with black you have covered the lens of the "projector" and all you see is the movie screen with no movie. When you start painting with white you are uncovering the lens and the movie begins to appear on your screen.

Is this any help at all???

[DannyRaphael]

Here are some links to what I've found to be very, very good tutorials on this subject.

Registration required on this 1st one, but it's very good and worth it. They don't send any annoying e-mails:
#1, part 1: http://www.shootsmarter.com/infocenter/sa005.html
#1, part 2: http://www.shootsmarter.com/infocenter/sa006.html

#2: http://www.webreference.com/graphics/column23/

#3: http://www.vrya.net/ts/photoshop7.php

#4: http://www.vrya.net/ts/photoshop1.php

[Leah]

Hi Neb --

To start off with, you are absolutely right. Black on a mask hides that part of the layer the mask applies to, and white on a mask reveals it.

You generally use masks with multiple layers and I think the confusion may be coming in because if you reveal some of the top layer (by painting with white on a mask) you are effectively hiding part of the bottom layer (because it's now covered by the top layer).

Try turning off visibility of all the layers except the one with the mask on it to see what effect the black and white is having on the individual layer and I think it will make more sense to you.

[nebgranny]

Thanks for the response I have not had time to really think them through as I have been busy with my grandchildren the past three days..will look and think more today. I appreciate the help!! Neb

[Swampy]

Neb

I too had some difficulty grabbing the concepts of masks, but then I worked a tutorial (ages ago) that made it simpler to comprehend.

The base image (a flower) was rather dark and called for adding a levels adjustment layer over the base image and filling the mask area for that adjustment with black. This completely oblitered the adjustment, but then the author of the tutoral said, "Now, let's paint the light back in. Use a a white brush on the mask and paint the light back into the petals." I've always considered that "painting with light".

It does get confusing, but basically you make an adjustment layer (levels, curves, hue, saturation etc.) then UNDO the correction by filling the mask for that adjustment layer with black. Then you REDO the adjustment, but only in the areas that you select by painting with the white brush.

The opposite would true if you made a correction then painted the mask with black to NOT apply the adjustment to a specific area. By default, all adjustment layers are filled with white and apply globally to the layer below. You have to manually fill the mask with black if you are going to paint in light (white) to resore the adjustment to specific areas.

[tell]

Hello Swampy. Great explanation.. I could add to that. After you have made an adjustment layer for example changed the image colour using colour balance, and filled the mask with black. Using a white brush to selectively brush back in specific areas of the image with the new colour. Then you can reopen the ajustment layer at anytime hitting on the image part of the adjustment layer, and alter only the new colour... Its a great way trick