When importing some flat TIFF files from Photoshop CS5 into After Effects CS6, AE asks what kind of alpha channel these images have — straight or premultiplied.
What type of alpha channel does Photoshop use for non-layered TIFFs?
This link may be helpful to you: http://help.adobe.com/en_US/AfterEffects/9.0/WS3878526689cb91655866c1103906c6dea-7f7ea.htm l
Alpha channels don't matter (since they are not transparency, and never get premultiplied).
But Photoshop writes TIFF composite image with the transparency premultiplied, since that is what 99% of TIFF readers expect/support.
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