RE: Best CI for process

From: Eric Neilsen ^lt;[email protected]>
Date: 10/02/05-10:46:13 AM Z
Message-id: <20051002164614.82A9E269C0C3@spamf3.usask.ca>

Have you printed these two negatives or step test to verify, with platinum
and palladium, that that is indeed the case?

  

Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
214-827-8301
http://ericneilsenphotography.com
> -----Original Message-----
> From: Sandy King [mailto:sanking@clemson.edu]
> Sent: Sunday, October 02, 2005 11:14 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Best CI for process
>
> Eric,
>
> Sorry, but a part of my last message was omitted during cut and
> paste.
>
> What I meant to have said was that although density range and
> CI (or
> Gamma, Average Gradient or whatever you want to call it) are
> related,
> the use of the former to talk about negative contrast can be
> very
> misleading because it often does not provide a good indicator
> of the
> effective printing density of a negative, while CI nearly
> always does.
>
> For example, consider the following three cases, which
> correspond to
> data from testing I did of TRI-X film, at nine minutes, 13
> minutes
> and 20 minutes.
>
> Time Dmin Dmax DR CI
> 9:00 .23 2.80 2.57 1.0
> 13:00 .30 3.11 2.81 1.0
> 20:00 .45 3.35 2.90 1.0
>
> As you can see, the DR increases significantly with time of
> development, but the CI, which is a much better indicator of
> effective printing density, does not. The negative developed
> for nine
> minutes will print with exactly the same contrast as the one
> developed for twenty minutes, though the extra B+F of the
> twenty
> minute negative will require more printing time. In other
> words,
> increasing time of development to obtain a higher DR range over
> that
> needed for maximum CI is just a waste of time which also
> results in
> longer printing times.
>
>
> Of course, if you are working with a film that has very linear
> straight line curve there will be a better correlation between
> DR and
> CI.
>
> Sandy
>
>
>
>
>
>
> >Sandy, I know they are.
> >
> >Eric Neilsen Photography
> >4101 Commerce Street
> >Suite 9
> >Dallas, TX 75226
> >http://e.neilsen.home.att.net
> >http://ericneilsenphotography.com
> >
> >> -----Original Message-----
> >> From: Sandy King [mailto:sanking@clemson.edu]
> >> Sent: Saturday, October 01, 2005 11:03 PM
> >> To: alt-photo-process-l@sask.usask.ca
> >> Subject: RE: Best CI for process
> >>
> >> Eric,
> >>
> >> Density range (DR) and contrast index (CI) are closely
> related.
> >>
> >> Read about it.
> >>
> >> Sandy
> >>
> >>
> >>
> >>
> >>
> >> >
> >> >
> >> > So a discussion of density range may be more appropriate
> than the CI
> >> for in
> >> >camera negatives intended for use in platinum/palladium
> printing?
> >> >
> >> >
> >> >
> >> >Eric Neilsen Photography
> >> >4101 Commerce Street
> >> >Suite 9
> >> >Dallas, TX 75226
> >> >http://e.neilsen.home.att.net
> >> >http://ericneilsenphotography.com
> >> >
> >> >> -----Original Message-----
> >> >> From: Ryuji Suzuki [mailto:rs@silvergrain.org]
> >> >> Sent: Saturday, October 01, 2005 7:19 PM
> >> >> To: alt-photo-process-l@sask.usask.ca
> >> >> Subject: Re: Best CI for process
> >> >>
> >> >> From: Richard Knoppow <dickburk@ix.netcom.com>
> >> >> Subject: Re: Best CI for process
> >> >> Date: Sat, 01 Oct 2005 16:36:06 -0700
> >> >>
> >> >> > Is it possible for you to post it on your web site
> >> >> > perhaps as a PDF, I think it would be of considrable
> value.
> >> >>
> >> >> PDF papers are ideal in my view but I am reluctant to
> do this to my
> >> >> photographic paper file. I'd rather mail a photocopy to
> someone in
> >> >> serious, legitimate need of the information.
> >> >>
> >> >> Although I might not condemn anyone putting scans
> online quietly, I
> >> >> probably don't want to know if my copy has anything to
> do with it.
Received on Sun Oct 2 10:46:34 2005

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