Problem
Motion-graphics renders contain transparent-edge darkening because premultiplied alpha is interpreted as straight alpha.
Solution
Root Cause / Diagnostic:
In premultiplied alpha files, color channels are pre-multiplied by their alpha transparency value against a solid background (typically black). When an NLE or compositor interprets a premultiplied asset as 'Straight (Unpremultiplied)' alpha, the application assumes RGB values contain zero background contamination. During compositing over light backgrounds, the black fringe baked into the semi-transparent pixels remains un-divided, creating an ugly, dark gray halo around all soft edges.
Actionable Fix:
1. Right-click the footage item in the project bin, select 'Modify' -> 'Interpret Footage', and set Alpha Interpretation explicitly to 'Premultiplied with Black' (or click 'Guess').
2. Alternatively, apply the 'Remove Color Matting' effect in After Effects to strip away the embedded background color fringe from semi-transparent boundaries.
3. Composite the graphic over a 100% pure white solid background to visually verify that anti-aliased edges are clean, sharp, and completely free of dark outlines.
Pro Tip:
Standardize studio render pipelines on Straight Alpha for all master intermediate graphics exports (ProRes 4444 or Animation codec) to prevent interpretation ambiguities across differing NLE platforms.
In premultiplied alpha files, color channels are pre-multiplied by their alpha transparency value against a solid background (typically black). When an NLE or compositor interprets a premultiplied asset as 'Straight (Unpremultiplied)' alpha, the application assumes RGB values contain zero background contamination. During compositing over light backgrounds, the black fringe baked into the semi-transparent pixels remains un-divided, creating an ugly, dark gray halo around all soft edges.
Actionable Fix:
1. Right-click the footage item in the project bin, select 'Modify' -> 'Interpret Footage', and set Alpha Interpretation explicitly to 'Premultiplied with Black' (or click 'Guess').
2. Alternatively, apply the 'Remove Color Matting' effect in After Effects to strip away the embedded background color fringe from semi-transparent boundaries.
3. Composite the graphic over a 100% pure white solid background to visually verify that anti-aliased edges are clean, sharp, and completely free of dark outlines.
Pro Tip:
Standardize studio render pipelines on Straight Alpha for all master intermediate graphics exports (ProRes 4444 or Animation codec) to prevent interpretation ambiguities across differing NLE platforms.