CI and platinum Negs

From: Eric Neilsen ^lt;[email protected]>
Date: 10/01/05-09:05:10 AM Z
Message-id: <>

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




> -----Original Message-----

> From: Sandy King []

> Sent: Saturday, October 01, 2005 9:12 AM

> To:

> 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




Eric Neilsen Photography

4101 Commerce Street, Suite 9

Dallas, TX 75226


Received on Sat Oct 1 09:07:04 2005

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