Re: Best CI for process

From: Sandy King ^lt;[email protected]>
Date: 10/01/05-11:50:35 AM Z
Message-id: <a06020418bf647b26ed2c@[192.168.2.2]>

The TRI-X toe is very long. It takes a log exposure value of about
0.5 to raise the useful part of the curve to about .15 over B+F, at
which point you have a shadow density of about 0.40. That would call
for using an EI of less than half the nominal value of 320.

I would add that if you want to use TRI-X with scenes that require a
lot of Zone expansion it would be best to fix the process exposure
scale at about 1.4. If you use straight palladium it is very
difficult to get enough contrast from TRI-X for anything over N+1, or
a SBR of about 5.5.

Sandy

>Sandy, speaking aobut Tri-X, how long is the toe in your tests? (in D log
>values). What EI do you use with it?
>
>
>Sincerely,
>
>Agustin Barrutia
>Bs As, Argentina.
>----- Original Message -----
>From: "Sandy King" <sanking@clemson.edu>
>To: <alt-photo-process-l@sask.usask.ca>
>Sent: Saturday, October 01, 2005 1:19 PM
>Subject: RE: Best CI for process
>
>
>>
>> Eric,
>>
>> As noted, my comments were predicated on the assumption that we were
>> talking about in-camera negatives and since density ranges of log 3.0
>> were mentioned I thought it important to point out that you can't get
>> there from here, i.e. no modern general purpose film will allow
>> development to a CI of 1.45 and over.
>>
>> If the subject is enlarged digital negatives or negatives enlarged on
>> high contrast continuos tone film DRs of this high are clearly
>> possible. I could, for exmaple, get a maximum DR of about 3.4 with my
>> Epson 2200 printing with black ink. At this point the question
>> becomes, is there any advantage to setting your process so that it
>> needs a negative with a DR of 3.0 instead of 2.0? I won't say
>> categorically that there is not but I will say that I have never seen
>> any visual proof of it. My experience is that so long as you have
>> adequate shadow detail you can set the process exposure scale pretty
>> much where you want it.
>>
>> As for the placement of shadow detail at .30 to .45, I have no
>> problem with that at all, *for some films". When working with a film
>> like TRI-X, which has a very long toe and a constant upward flare in
>> the shoulder, overexposing to get shadow detail out of the toe and
>> into the straight line (if we may call it that) part of the curve is
>> a very good thing because it increases separation in both the shadows
>> and in the highlights. On the other hand, if you overexpose with HP5+
>> you will increase separation in the shadows, but shoulder compression
>> will result in less separation in the highlights.
>>
>> Sandy
>>
>>
>> >Sandy, Most of my work is in doing enlarged negatives and while the
>> >discussion did start out to be about in camera negative development and
>> >placement of shadow density, it did get into the density range issue. My
>> >large format camera is 4x5, so most of my negatives reach their final
>> >expression through the enlarged negative process.
>> >
>> >
>> >Since Kodak's 4125 has bit the dust as did 4127, I have been looking for
>a
>> >film that was so complete for both darkroom and some in camera work. Some
>> >have come close, but most pail in comparison due to the lack of range.
>> >
>> >In print making, there is no law that says, it must all be done in one
>> >solution. Expanding the capabilities of the film by use of toning,
>> >bleaching, etc, are fair game. The key is adequate exposure to get your
>> >detail off the non responsive area within the toe. To that end, I find
>that
>> >.3 to .45 above is a good place to start placing your detail.
>> >
>> >
>> >Many early computer generated negatives that were sent to me for
>printing,
>> >severely lacked shadow separation and were buggers to print.
>> >
>> >
>> >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: Saturday, October 01, 2005 9:12 AM
>> >> To: alt-photo-process-l@sask.usask.ca
>> >> Subject: Re: Best CI for process
> > >>
>> >>
>> >>
>> >> A negative with a DR of 3.0, let's say one that has a B+F of
>> >> log .30
>> >> and a highlight reading of 3.30, must by necessity have a CI of
>> >> over
>> >> 1.45. The problem is that there are very few films, if any,
>> >> that can
>> >> be developed to a CI of 1.45. Most films are not even capable
>> >> of a CI
>> >> of as much as 1.2. Once they reach a CI of 1.2 any further time
>> >> in
>> >> the developer simply increases density equally on all parts of
>> >> the
>> >> curve, from the shadows to the highlights, but it does not
>> >> increase
>> >> CI. In other words, you may develop longer and push the
>> >> highlight
>> >> density to log 4.0 or above, but any density over that reached
>> >> at the
>> >> point of maximum CI is just garbage density. You might as well
>> >> take a
>> >> piece of opaque plastic and insert it between the light source
>> >> and
>> >> the sensitized paper.
>> >>
>> >> Choice of developer, whether staining or not, is basically
>> >> irrelevant
>> >> as a factor with regard to the maximum potential CI of a film
>> >> since
>> >> this is quality is pretty much built into the film. Of course,
>> >> if you
>> > > use a very energetic formula you will reach the maximum CI
>> >> sooner in
>> >> development, but it is not possible to push the envelope.
>> >>
>> >> Since this discussion emerged from a discussion on developing
>> >> for
>> >> shadow density with in camera negatives I assume that the
>> >> subject
>> >> continues to be this type of negative, as opposed to enlarged
>> >> digital
>> >> negatives or negatives enlarged on lith film. In those cases it
>> >> may
>> >> be possible to reach a CI of 1.45 or higher.
>> >>
>> >> However, assuming that the subject is in camera film, and sheet
>> >> film
>> >> also since we are talking about contact printing in palladium
>> >> or
>> >> platinum, the question remains, which modern films are capable
>> >> of
>> >> being developed to a CI of 1.45?
>> >>
>> >> Sandy
>> >>
>> >>
>> >> Etienne wrote:
>> >>
>> >> >Sandy wrote:
>> >> >
>> >> >> So let me ask again. What
>> >> film/developer/agitation/temperature
>> >> >> combination should one use for N development of in- camera
>> >> negatives
>> >> >> when the density range required for scenes of normal
>> >> contrast is log
>> >> >> 3.0 or above?
>> >> >>
>> >> >> And what should one do when the scene requires N+
>> >> development?
>> >> >>
>> >> >> My best estimate for most common films is that you can't
>> >> get there from
>> >> >>here.
>> >> >
>> >> >I don't understand the question. The DR of the negative that
>> >> just "fits" a
>> >> >given printing process doesn't change with the scene contrast
>> >> -- it is a
>> >> >matter of (1) FB+F plus the image density necessary to get up
>> >> off the toe,
>> >> >and (2) the Dmax of the film at the shoulder. Neglecting the
>> >> small rise in
>> >> >FB+F that accompanies longer development, one just develops
>> >> until the
>> >> >highlight densities are log D 3.3 or whatever.
>> >> >
>> >> >Note that users of staining developers may find that the
>> >> increase in FB+F
>> >> >is NOT negligible. (Ditto constant-agitation developing, but
>> >> to a lesser
>> >> >degree.) M-Q or P-Q developers, or even the non-staining pyro
>> >> formulae,
>> >> >used with intermittent agitation, do not have this problem. I
>> >> develop in
>> >> >glycin, which is perhaps the least fog-prone developing agent
>> >> known, and
>> >> >have never had any problem, even using constant agitation for
> > >> 30+ minutes
>> >> >at 75 degrees F. [Side note: beware of any glycin you receive
>> >> that is
>> >> >darker than a sheet of Crane's Ecru paper -- although many
>> >> internet sources
>> >> >say it works fine, IME it does not. It should be just barely
>> >> off-white.
>> >> >I'm speaking from extensive experience here -- I suspect I've
>> >> mixed more
>> >> >glycin developer since commercial glycin developers have been
>> >> off the
>> >> >market than the next 10 glycin users combined.]
>> >> >
>> >> >If one's film and/or developer will not produce the required
> > >> highlight
>> >> >density (or will not produce it without excessive FB+F), there
>> >> is still
>> >> >hope. Super-proportional intensification (if the shadows are
>> >> already at
>> >> >the correct density and the highlights are insufficiently
>> >> dense) or
>> >> >super-proportional reduction (if you expose more to get the
>> >> highlight
>> >> >densities up where they belong and the shadow densities are
>> >> too high), or
>> >> >both, can expand DR by log D 1.0 or so. I have even made HP5+
>> >> negatives
>> >> >with a DR of 3.0 this way, although I don't care for the film
>> >> and stopped
>> >> >testing.
>> >> >
>> >> >Best regards,
>> >> >
>> >> >etienne
Received on Sat Oct 1 11:50:50 2005

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