Premultiplied alpha

A way of storing transparency in which each pixel's colour has already been multiplied by its alpha. The alternative, straight alpha, keeps colour and alpha separate. Reading a file as the wrong one gives dark or bright fringes at the edges.

In Premation

A file's alpha mode is read once, at decode, under Interpret Footage ▸ Alpha on the asset. Past that point everything in the engine is premultiplied.

Read the docs: The render model

Related terms

• Alpha channel
• Compositing