2009.04.27 19:49 "[Tiff] Question regarding unassociated alpha", by Amir Ebrahimi

2009.04.27 20:07 "Re: [Tiff] Question regarding unassociated alpha", by Chris Cox

Probably a bug.

Lots of people get alpha channels confused with transparency (associated alpha), especially in the 3D and video world. They forget that you can have alpha channels that are not transparency(associated) and you can have more than 1 alpha channel in a single file.

Chris

________________________________________
From: Amir Ebrahimi [amir@unity3d.com]
Sent: Monday, April 27, 2009 1:03 PM
To: Chris Cox
Cc: tiff@lists.maptools.org

Subject: Re: [Tiff] Question regarding unassociated alpha

On Apr 27, 2009, at 1:00 PM, Chris Cox wrote:

Unassociated alpha should never be premultiplied - it is not associated with the color channels. Only assoicated alpha should be premultiplied.

Chris

I agree. Why is libtiff doing this?