[alt-photo] Re: Development By Inspection Methods

[Francesco Fragomeni]

Ken has asked that I expand a bit on DBI via green light advise I've
received.

I had dinner with Michael Smith and Paula Chamlee two days ago and we
discussed the topic a bit. The green safelight method is their preferred
method. We discussed my issue with 400 speed film gaining extra density in
the film base and it was their opinion that it actually should make a
difference that there shouldn't be any issue printing through it. They are
using 20 year olf Super XX film and they get film base densities in the
range of 0.5 (due to age) and trust me when I say that this is having
absolutely no negative effect on the quality of their prints.

Michael's preference is to focus on the base side of the film while Paula
looks at both the emulsion side and the base. The key is simply to
recognize what proper density looks like primarily through the base side.
There really isn't much instruction beyond what Michael wrote about in his
well read article on DBI. The green light is left on only for a moment and
a judgement is made to either end development or continue it.

I will probably give it a try but I'm going to first try printing the negs
with the extra film base density to see how they print and if all is good
then I'll stick with my IR method.

-Francesco

On Thu, Mar 8, 2012 at 12:21 AM, Richard Knoppow <dickburk at ix.netcom.com>wrote:

>
> ----- Original Message ----- From: "Francesco Fragomeni" <
> fdfragomeni at gmail.com>
> To: "The alternative photographic processes mailing list" <
> alt-photo-process-list at lists.**altphotolist.org<alt-photo-process-list at lists.altphotolist.org>
> >
> Sent: Wednesday, March 07, 2012 7:47 PM
> Subject: [alt-photo] Re: Development By Inspection Methods
>
>
>
> Thanks Ken,
>>
>> I've found a few things written about Pinacryptol Yellow and Pinacryptol
>> Green that I had not previously seen. They echo your experience with the
>> desensitizer reducing the speed of the film significantly. I've also found
>> reports that it may not work or be effective with modern faster films. I
>> was hoping that these desensitizers would be more useful then they
>> apparently are and I suppose that explains why they are nearly impossible
>> to get a hold of these days. If there was anything magical about them
>> they'd probably be in use today.
>>
>> I'm very interested in what I'll be able to do with the green safelight
>> technique (minus the desensitizer). I use 100 and 400 speed films. My only
>> concern is whether or not 400 ISO film will be dramatically more apt to
>> fog
>> using the technique. I understand that the green safelight is only on for
>> a
>> few seconds at a time and kept at a safe distance and I get that the film
>> desensitizes as it develops but I' still concerned that faster film will
>> fog. Anyone have any experience developing 400 ISO film this way? Are
>> there
>> any problems with it?
>>
>> -Francesco
>>
>
>   FWIW, the theory behind using the green safelight is that its peaked at
> the color the eye is most sensitive to when dark adapted. As a result it
> can be dimmer than light of another color for the same visual brightness.
>  Also, until recently, panchromatic films had a dip in the sensitivity in
> the green. Have a look at the published spectral sensitivity curves for
> film to see what I mean. Its slight but there.  More modern pan films like
> T-Max and other tabular grain films tend to have more uniform sensitivity.
>  Also, most developers act as desensitizers so that after half the
> developing time the film has lost much of its sensitivity and so the light
> is less likely to cause fogging. Nonetheless, the green safelight can be
> used for only a few seconds. I've found that judging densities is difficult
> especially since the undeveloped halide results in the film looking quite
> different from the way it does after fixing.
>   I think there are circumstances where development by inspection may be
> necessary but film is very uniform so that development by time and
> temperature can result in very predictable results provided some care is
> used so I think development by inspection should be reserved for those
> times where there is something unusual that makes it necessary.
>
> --
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk at ix.netcom.com
> ______________________________**_________________
> Alt-photo-process-list | http://altphotolist.org/**listinfo<http://altphotolist.org/listinfo>
>