From: Sandy King (sanking@clemson.edu)
Date: 07/17/02-08:38:52 PM Z
Richard Knoppox wrote:
>
> >You might also try Kodak's D-19, a very energetic developer that will
>>give you about as much contrast as you can get outside of a staining
>>developer. Zoe Zimmerman, whose work was featured in a recent issue
>>of View Camera, mentioned at the Large Format Conference in
>>Albuquerque that she uses D-19 for negatives she intends to print in
>>albumen, which requires a density range of 1.8 and above. I don't
>>know if D-19 is still packaged by Kodak, but if not you can find the
>>formula in a number of sources.
> >
>>However, my personal opinion is that to get any snap in your print
>>with HP5+ from a really low-contrast scene you will be better off
>>with either ABC+ or Pyroca-HD since the effective printing DR with
>>these developers will be much greater than the actual DR read by a
>>densitometer because of the actinic stain.
>>
>>Sandy King
>>
>>
>>--
> D-19 has a lot of bromide in it. It was originally intended as a
>developer for
>x-ray and special purpose films where high contrast but not extreme
>contrast was desired. The bromide will reduce film speed a little.
I had been interested in seeing how D19 might work with HP5 since
talking with Zoe Zimmerman in Albuquerque so Shannon's message
prompted me to carry out some exposure/development tests today with
this film/developer combination. I found the results very
interesting, and potentially quite useful for someone needing to get
a high CI from HP5+ to allow some N+ development in very low contrast
scenes. Here is what I did and found.
1. The tests were carried out as I usually test film, following the
procedures described by Davis in Beyond the Zone System. Five sheets
of HP5+ film were exposed to a Stouffer TR45 step wedge at 0.5
seconds at f/22 with an enlarger controlled by a Metrolux integrator,
accurate to 1/100 of a second. An 80A filter was used with the
tungsten bulb of the enlarger to approximate daylight exposure.
2. The five sheets of film were developed in BTZS type tubes for 3,
5, 8, 12, and 18 minutes. The developer, freshly mixed D19, was used
at a temperature of 70F, maintained with a water bath throughout the
period of development. Agitation was constant, rolling the tubes in
the water bath at a moderate speed.
3. After drying the five sheets of film were read with a densitometer
and the results plotted with Davis' Plotter program.
Results
The exposures of 5,8 and 12 minutes were virtually identical, ranging
from a CI of 1.07 at 5 minutes to 1.11 at 12 minutes. The actual
density reading at Step 1 and 21 for these development times were as
follows.
3 min 5 min 8 min 12 min 18min
Step 1 2.61 2.84 2.98 3.04 3.10
Step 21 .17 .19 .22. .26 .28
When plotted the 5, 8 and 12 minute exposures suggest that we would
be able to get about N+1 development from HP5+ and D19, even when
working with a standard DR of 1.6. This would result in a negative DR
of about 1.6 even in very flat lighting (when the SBR is 5). That is
really pretty impressive and quite a bit more contrast than I
expected form the combination.
A really interesting thing about the results is that this combination
gives you a huge amount of latitude in time of development since, as
noted above, the CI changes only from 1.07 to 1.11 in going from 5-12
minutes of development, and b+f increases very little with increasing
time of development. In this case HP5+ reaches close to gamma
infinity at about 8 minutes but for all practical purposes the 5, 8
and 12 minute negatives would have almost identical printing
characteristics both in terms of print contrast and exposure time.
Emulsion speed is also almost identical for the 5, 8 and 12 minute
develoment times.
Bottom line is this. If you happen to be working in a scene of very
low contrast, ie. SBR of 5, D19 will definitely bump up the contrast
of your negatives to the level where it should be able to make a
snappy print. And within reason you don't even have to be concerned
with time of development, as times of 5-12 minutes give about the
same result in terms of CI.
Sandy King
--
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