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From: ems@amdahl.UUCP (ems)
Newsgroups: net.rec.photo
Subject: Re: Product Quality: Color prints from slides (contrast buildup)
Message-ID: <2141@amdahl.UUCP>
Date: Wed, 23-Oct-85 13:22:34 EDT
Article-I.D.: amdahl.2141
Posted: Wed Oct 23 13:22:34 1985
Date-Received: Fri, 25-Oct-85 02:52:41 EDT
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> >> Reversal color print processes are not as good as negative print
> >> processes. ...
> >
> >Ever hear of Cibachrome? The results are luminous. ...
> 
> Sorry, Cibachrome DOES NOT provide the order of results you are looking for
> UNLESS you shoot the original slide with a Ciba print in mind.  This is because
> the color saturation and contrast increase inherent in the print process
> CANNOT be controlled to match print to slide.  However, if you overexpose the
> slide, you wind up with a washed-out slide that makes a pretty good Ciba
> print.  It's a no good slide for anything else, though. ...
> 
> The problem with making prints from slides is that by their nature slides can
> contain more information than a print can.  If you compare the range of trans-
> mission densities possible through a slide with the reflection density range
> possible from any print, the print loses.  The density range on paper, no matter
> what the process, is limited to around 2 f-stops, and that's with ideal illumin-
> ation and display, while the slide is theoretically unlimited.  Since the
> density range of "reality" is quite wide (making metering a process of
> judgement), a slide can better match reality.  The limits to the process are
> fundamental.
> 
Something which has always bothered me, when you copy a print onto
a slide (an perhaps other copies as well) you get 'contrast buildup'.
It seems to me that if the contrast range of the print is *less*
than that of the original subject, then the contrast range of the
slide should also be *less* than the original.  So why does the
slide show *higher* contrast?

I'm sure there is some simple inversion of logic that I am doing
somewhere.  Some trivial point I have missed...  But miss it I have.
I hereby cast my reputation for clear thinking onto the net to be
ripped to shreds ....   (Isn't it amazing what one will suffer to
get an answer to an anoying problem?)

-- 

E. Michael Smith  ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems

'If you can dream it, you can do it'  Walt Disney

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