2003.02.04 04:04 "Re: Pre-multiplied alpha", by Chris Cox
Has anyone noticed that Photoshop 6 has changed its handling of pre-multiplied alpha from tiff images from Photoshop 5? Namely, it seems to no longer recognize pre-multiplied alpha.
Sorry, but nothing changed in that regard.
TIFF specifies that images with transparency (at least one associated alpha channel) must be premultiplied (black for RGB/Grayscale, white for CMYK), and Photoshop has always and will continue to treat it that way until the TIFF specification changes.