Mattes are vital in visual effects compositing. They control the transparency of the layers that we work with. And one word often associated with mattes is premultiplication. But what does that actually mean?
This video provides a detailed explanation of what a premultiplied image is, and how we can create one. Hopefully, after watching this video you will have a good understanding of how mattes actually work to create transparency in compositing.
Although I use Nuke in my examples, these concepts apply to all VFX compositing and image manipulation software.
You can find a text version of this tutorial at my website: http://conradolson.com/premultiplication
