[Bf-funboard] Transparency, Mixing settings

[Doug Ollivier]

Hi Guys.

I have noticed when saving images with transparency that the same colour 
mixing setting does not open in photoshop the same way.

For example when saving to PNG the Key setting is most likely correct, 
as it is not mixing the transparent pixels with any colour. Whereas the 
TIFF format seems to take Pre-mul images as default for the same outcome 
(Key looks very strange on tiff).

I am curious if each format has a specification as the how Transparency 
should be handled. 

It makes me think there is an opportunity for a "Auto" transparency 
setting that looks at the selected image format and chooses the standard 
settings.  Yet one more thing that the user does not need to think about.

If transparency is specified, I would be happy to do some research and 
come up with a list of "Automatic" transparency settings for the various 
formats.  The Auto transparency setting could also be used to avoid RGBA 
channels being saved to RGB formats like JPG, as it could just override 
that channel being saved.

Doug.