2008.04.17 21:14 "Re: [Tiff] a question about creating transparency of the image in TIFF", by Chris Cox
There are 2 types of alpha in TIFF: associated (transparency) and unassociated (undefined extra channels).
Also, the TIFF spec. states that images with associated alpha (transparency) must be premultiplied.
On 4/17/08 8:18 AM, "Gerben Vos" <Gerben@zylab.com> wrote:
Константин Луцкий wrote:
Hi. Can anyone help me? How can I create transparency of the image in TIFF?
Frank Warmerdam wrote:
The conventional approach is to create an alpha sample for each pixel, and set it to indicate transparent pixels.
For example, for RGB images (PhotometricInterpretation = 2) you can set SamplesPerPixel to 4, and then indicate in the ExtraSamples tag that the extra (fourth) sample is an alpha channel. Read the TIFF specification for more info.