Mask Questions: NO BUG'S PLEASE....

[ggroess]

I would like to start a new topic on Masks. 
I want to discuss the functionality of the mask tool without mixing bugs into the dialog. 
If my questions are coming about because of a bug, then that should spawn a new thread. 

My first question about the masks is this...
If I select the mask on the ribbon should it not also select the mask in the curves grid?  Is there a reason It would not do that? 
I can think that you might want to see the effect of the mask but I seem to be missing the point.  If I use the ribbon controls to I would expect them to make the grid match the image.   

Do I want the mask to be almost black and white??  or am I looking to make the areas I want to change grey?  I know you are talking about coloring the masks...If they were red would they become "pink" in some areas? 

I'm starting to see the forest...but the trees are still getting in the way...
Greg

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Hi Greg,

Normally there will be no effect from showing the mask.  I've added Gloria's suggestion that the tab for the mask curve include the name of the mask.  What will happen is the mask will act as a soft edged "stencil" that controls what the curve will do.

To see the areas a particular mask covers, I find myself setting the image to all black, and seeing what happens to the image.  The black areas will be changed while the others won't.  Or I can move either endpoint of the a or b channel of Lab, and the colored areas are the parts affected by the mask.

Here's an example.  In this Lemur picture, try bumping the colors in Lab, using the slider.  The thing that will eventually stop you from adding color is that you'll see bright orange demon eyes.  If you're a color maniac like me, you may want to increase the color of the rest of the image some more, but the eyes stop you.  Enter masks.  Select the Saturation channel of HSB as your mask, and invert it.  Now the eyes are dimmed down in color, while the less saturated parts of the image retain their new luster.  It's now possible to move the saturation slider to the right some more, giving even more color to the intermediate objects in the image such as fur and wood, leaving the eyes and green grass more or less alone.

Re your comment about the mask being almost black and white - the answer is yes, or at least it's generally good to increase the contrast of the mask.  In the case of the lemur image, fine tuning the mask channel with curves, by moving the black end horizontally in, helps out even more.

Another very common example is skin tones, where you may want to bump saturation in the objects in the image, while leaving skin tones alone.

[ggroess]

So what you are saying..without putting words in your mouth...

Is...
It matters not what color space or channel I use to create the mask...I choose that based on my goals.  If I want to turn my wife's scrubs from Blue to yellow I would choose the channel that makes them look the darkest black since that is the only effected area. 

I would then adjust the color in the color space I choose and only the areas masked would be effected.  If I choose S out of HSB only the saturation is effected...etc...

Have I got it right so far??

Greg

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Close - it's the lightest areas that are affected the most.  The way I remember is that "zero value means zero effect".  Whether the curve affects saturation or not is dependent on the curve, not the mask.  The mask acts as a passive "stencil" for what the curves do to the image.

I'm about to do a new version that displays a colored overlay for each mask, so the areas that are not red are the ones that the curve will change.  I think once that is in place it will be easier to see what is happening on your actual image.

[mikemeister_admin]

Oh, for Pete's sake :) ..."zero value means zero effect" That is such a software creator thing to say.
'Black conceals, white reveals'. That's how real people remember it!

g

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I like it - sounds like something from Harry Potter :-)