Digital BW, The Print

>One last thing to look for that I don't think has been mentioned
>directly is a gamma mismatch between the Gray Space and the RGB
>Space. Dan Culbertson posted a good method to make the transition
>from Gray to RGB if you are unsure if the gamma's match or not.
>
>"2.Convert it to RGB.(note -be sure to convert to an RGB space
>identical in gamma to the source grayscale space. If you are not sure
>then convert to multichannel, make two duplicates of the grayscale
>channel, then convert to RGB. This will sidestep any gamma change
>when converting to RGB)."
>
>Check you image histogram before and after the gray to RGB
>conversion. If they are not the same, the gamma's don't match.

Martin -

I just did all that. The sRGB space is also gamma 2.2 according to one of
this morning's messages, so there's no mismatch there. I also checked an
image histogram before and after converting from Gamma 2.2 grayscale to
sRGB; apart from half a dozen very short single-tone spikes in the RGB
version that weren't there in grayscale (a LOT milder than would be created
by a very conservative change in Curves or Levels), the curves look
identical.

Please see my message of this morning (replying to Todd) for more discussion.

-- Nick

NICHOLAS HARTMANN                                +1 (414) 271-4890
611 N. Broadway, Suite 509                  fax: +1 (414) 271-4892
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Technical and scientific translator:  German and French -> English