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Creating Varied Transparency Mask

Posted: 29 Jul 2020, 17:40
by pixelpusher
Hello all.
I am interested in figuring out how to take a grey scale image, and make it a mask maintaining the various levels of grey as various levels of transparency.
So black would be o% transparent and white would be 100% transparent.
I can't figure out a good approach to this.
The various key tools allow for filtering a range to a fully opaque mask, not what I want.
I want a variable matte, maintaining the variety of density driven by the greys.
Any direction appreciated.
Stay safe and well!
Casey

Re: Creating Varied Transparency Mask

Posted: 29 Jul 2020, 17:58
by slowtiger
The Scan cleaner would transfer a bw image into these transparencies, but TVP can't use this as a mask on a different layer the same way as it peserves alpha on the same layer.

Re: Creating Varied Transparency Mask

Posted: 30 Jul 2020, 06:27
by ematecki
Yes it can :)

You have to activate "Stencil" on the gray-level layer, and then it will only draw (in any layer) where there is already opacity in this layer.

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Re: Creating Varied Transparency Mask

Posted: 30 Jul 2020, 06:30
by Hironori Takagi
I'm interested in this issue and created a custom panel that behaves the same as the After Effects plugin "Unmult".
WhiteOnOff(e)_200730.png
Is your goal different from this?

Re: Creating Varied Transparency Mask

Posted: 30 Jul 2020, 19:38
by pixelpusher
Yes, my goal is different.
I am interested in maintaining the full 256 steps of potential variation in transparency of a mask, (or alpha whichever you prefer) driven by the grey scale of the source image(s).
So were it a full color image, first step is a black and white conversion. No problem. Then a conversion to a variable density mask/alpha image based on the grey scale. 0% black = 100% transparent, 25% black = 75% transparent 50% black = 50% transparent 75% black = 25% transparent 100% black = 0% transparent, and every step in between these as well. Equivalent to a gradient mask/alpha driven by the image.
Thanks for the interest and feedback on this.
Scan Cleaner does not do this in my estimation. It is more like the color keying tools and isolates a range that then is the mask/alpha.

Re: Creating Varied Transparency Mask

Posted: 30 Jul 2020, 21:18
by ematecki
Ok, I misunderstood...
Convert to B&W.
Then try the Luma Keyer with these values :
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Because of data validation, you have to input the 255s from right to left...

Re: Creating Varied Transparency Mask

Posted: 31 Jul 2020, 15:59
by pixelpusher
Thanks ematecki!
This was a great solution to what I was trying to do!
I so appreciate your assist.
Be well and thank you!