RE: Best CI for process

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