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1999.07.16 19:40 "Re: RGB Gradient Code, adapted from Andreas Neumann (sol'n)", by Eric B Middlecamp

"Grissom, Ed" <egrissom@ziimaging.com> on 07/16/99 02:36:10 PM

To:   Eric B. Middlecamp/MIPP/Imation@Imation
cc:
Subject:  RE: RGB Gradient Code, adapted from Andreas Neumann



>
> Eric -
>
> I _know_ from some discussion on comp.graphics.apps.photoshop that PS does
> fiddle with your data WHEN THE DEPTH OF EACH BAND IS GREATER THAN 8bits and
> it must be converted for display.  They do some random dithering that is not
> really documented well, but the prepress people like.
>
> In your case, I know that you have 8bit bands, so the above does not come
> into play.  However, given the above, it seems reasonable that PS is doing
> something and they are not telling you the truth about your image.  I think
> the problem is in PS, not LibTIFF...
>
> Actually, I now seem to remember some folks talking about only having 7bits
> per band of "true"
> data in PS.  Don't remember the specifics of that though.... Talk to
> Adobe...
>
> --
> ed grissom
> egrissom@ziimaging.com
>
> > ...
>

Everyone,

I've found the culprit, and as it turns out it could be potentially embarrasing,
so.. go easy on me. In Photoshop, under profile setup, there was a default
("dont ask") conversion in place for RGB images. Having removed this, everything
is as it should be. Sigh.

Many thanks for the feedback,
Eric Middlecamp