Greyscale PNG to Alpha Mask

[alans]

Hello,

I think that this is going to be a simple question to answer since I believe that I am missing a fundamental understanding on what format the alpha masks need to be in.

I'm having a heck of a time trying to create my own alpha mask from the following image. I want the outside of the box to be 100% transparent, the border to be opaque, and the inside to be slightly transparent:


I want to apply the mask to this image:


I have tried many different combinations of
• Dropping the depth of the alpha.png image.
• Removing the alpha of the alpha.png image.
• Converting the alpha.png image to another image format.
• Anything else I could find on forums that looked like it did what I wanted.

Can anyone let me know how I can convert the alpha.png image into a true alpha mask to use?

Thanks!

[fmw42]

try

convert image.png alpha.png -alpha off -compose copy_opacity -composite result.png

but if you want to get rid of the slight halo around the white border, then you need to make sure that your black is completely black, which it is not currently.

convert image.png \( alpha.png -black-threshold 50% \) -alpha off -compose copy_opacity -composite result2.png

see
http://www.imagemagick.org/Usage/compose/#copyopacity
http://www.imagemagick.org/script/comma ... -threshold

[alans]

Thanks!

This worked like a charm.