If you edit a vignetted image in Lightroom, is it possible to get an alpha channel or transparent layer of that vignette shape? This would help production teams in situations where a vignetted image is placed over a colored background.
If you or they have Photoshop it seems you could accomplish what you're asking by applying the vignette to either a pure black or purge white image, depending on whether the vignette is lighter or darker than the image, and open that in Photoshop and then copy/paste it into a new image as the layer mask.
I am currently working on creating a UI design which attempts to address some of the ideas and discussions you all are having in regards to the post-crop vignette feature in Adobe Photoshop Lightroom. During my research, this topic (among others) are helping to inform the future design ideas of the post-crop vignette.
Firstly, I just wanted to thank you all for contributing to the forum and sharing some great information and ideas.
Secondly, I wanted to share my progress with the project. It can be seen on Behance here http://on.be.net/1ADdZAa. At the time of this writing I am exiting the Research/Discovery phase and getting started on the Design Phase. If you have any comments or feedback, I would love to hear it.