AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2002.03.05 14:53 "Photoshop Alpha Channel", by Hulme, Phil
2002.03.05 17:32 "Re: Photoshop Alpha Channel", by Andreas R. Kleinert
2002.03.05 20:58 "Re: Photoshop Alpha Channel", by Chris Cox
2002.03.06 00:46 "Re: Photoshop Alpha Channel", by Peter Montgomery
2002.03.06 01:36 "Re: Photoshop Alpha Channel", by Chris Cox
2002.03.06 07:36 "Re: Photoshop Alpha Channel", by Peter Montgomery
2002.03.06 08:15 "Re: Photoshop Alpha Channel", by Chris Cox
2002.03.06 23:32 "Re: Photoshop Alpha Channel", by Daniel McCoy
2002.03.07 18:58 "Re: Photoshop Alpha Channel", by James Burgess
2002.03.06 08:55 "RE: Photoshop Alpha Channel", by Hulme, Phil
2002.03.06 22:32 "RE: Photoshop Alpha Channel", by Chris Cox

2002.03.07 18:58 "Re: Photoshop Alpha Channel", by James Burgess

1 - Open a blank image
2 - Draw anything on it. Make it small enough that you can see the
background checker pattern.
3 - Save it as a PSD.
4 - Save it as a TIFF.

5 - Open both the PSD and TIFF and compare them. The PSD will maintain the alpha channel while the TIFF file will have been merged over white with no sign of transparency.

Second, you didn't save the TIFF with transparency. If you save the TIFF with transparency, it won't be flattened.

This is inexcusable.

This is user error.

See above.

Peter,

As an independant observer I just tried this. If you repeat your experiment above with PhotoShop 7 or 6 you will get the result I think you thought you should. Don't know about 5 though. You do to have turn on "Advanced TIFF options" in preferences whioch then lets you check "Save Transparency". Looks to me like the alpha is even pre-multiplied.