How to adjust the opacity of a mask without affecting the image underneath?

[Stephen Smith]

I’m not sure I’m a 100% sure what your asking, but have you tried the Vignette filter? Hope this helps.

Stephen Smith
Lone Peak Producitons

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[Gareth Randall]

Thanks Stephen. I tried it, and it’s certainly nearer to what I want, but the soft edge you can get with the Vignette filter isn’t as nice (or as simple) as feathering an image mask.

As to what I’m actually asking – I’ve got a background texture, and I want to vignette it to give it a bit more interest and depth. So I draw an oval mask, apply it to the texture and feather it. Of course, the mask is 100% black apart from the feathered edge, but that’s too much for the look I’m after.

I want to drop the opacity of *just the mask* to about 75%, so I can see the texture coming through the masked area, but here’s the problem: if I adjust the opacity slider of the mask, Motion adjusts the opacity of the texture as well. If I knock the mask opacity down to 75%, the texture opacity goes down to 75% too. This happens even though you specifically select the mask layer.

I guess I’m just surprised that you can’t adjust the opacity of a mask separately from the image you’ve applied that mask to. Motion makes so many complicated things so simple, it’s weird that it makes something so simple so complicated.

[Andrew Penick]

in hindsight it’s obvious.

You have to remember that a mask is a full image, not just the shape you’ve created. When you set an image to a Mask, Motion will look at the values and determine opacity. White is opaque, black is transparent, and gray is a value of opacity somewhere in between.

When you lower the value of opacity of the blurry circle, you moving it from white to a shade of gray–making the whatever you have applied the mask to become more and more transparent.

Instead of applying a mask to your image, what you should consider doing is creating group above your background that contains the following:
1. a black solid that is larger than your canvas
2. a white circle or other shape for your vignetted area
3. a gaussian blur layer to blur everything in this group

Then set this whole group to Multiply. Presto! your custom vignette.

I change the world.

[Gareth Randall]

Andrew, you’re a star. You have, indeed, changed my world 🙂

I only wish I really understood how the different transfer modes work. I just tend to cycle through them until I see either the result I want or a result I like.