Black and white processing in a JOBO
Aleksandar Zivanovic Blg 95
A while ago I bought a second hand Jobo processor (CPE 2). I have not
yet got into colour printing but I plan to. In the meantime, I have used
it to process my black and white films. I have two questions:
I use Tmax developer to process my Tmax 100 films. The information given
about making up solutions is not terribly helpful: I would like to use
the solutions once and throw them away. What concentration should I use
in the rotary processor ? (I need 240 ml of solution.)
Is there any advantage in processing Multigrade prints in the rotary
procesor as compared to trays. (I tend to use 8"x10", low volume).
thanks for any info
Aleks
Guy de Riencourt
results conducted by magazines and I did some tests to will show you
that with Tmax 1+4 you will get the best out of the straight line of
TMX.
>Is there any advantage in processing Multigrade prints in the rotary
>procesor as compared to trays. (I tend to use 8"x10", low volume).
some help if you want to do 20*24 inches, then it is nice not having to
mess up with trays.
>thanks for any info
>
>Aleks
<deri...@micronet.fr>
Paris, France
Guy de Riencourt
>Aleks,
>
>Tmax in Tmax: Because the rotary processor gives continuous
>agitation, you will need a weaker developer dilution to
>avoid overdevelopment (probably severe) or unacceptably short
>development times. For example, when I develop 35mm Tmax100 in
>Tmax developer I use manual agitation and a dilution of 1:5
>(6.5min @ 75F), but when I develop 4x5 sheet Tmax100 in Tmax
>developer using my JOBO I use a 1:9 dilution (9.5min @ 75F).
>Both methods give the same degree of development, measured
>densitometrically (and both used one-shot). If I were to use a
>1:5 dilution for 6.5min for the sheet film, I'd get a negative so
>overdeveloped that it would be unprintable (unless the scene was
>incredibly flat).
>Mark Gunion
>mwgu...@ucdavis.edu
>
I disagree with this. The dilution of the developer changes the
shape of the curve! Increasing the dilution won't give you the
maximum you can get out of TMX film. If you have access to a
densitometer you will see that from a dilution of 1+4 and 1+7 the
shape of the curve changes. You will get less of a straight line,
that makes TMX what it is as a film.
If you say that you prefer the look of the other dilution then I
will stop discussing because subjectivity gets involved.
If you have problems of too short a time in the developer, try
developing at 20 Celsius (68F) and prewetting the film for 5
minutes. This will speed down the development.
For 4*5" using the 3000 series drum I develop N-1 for 5'00" and
get good results.
Guy
<deri...@micronet.fr>
Paris, France
Mark Gunion
Tmax in Tmax: Because the rotary processor gives continuous
agitation, you will need a weaker developer dilution to
avoid overdevelopment (probably severe) or unacceptably short
development times. For example, when I develop 35mm Tmax100 in
Tmax developer I use manual agitation and a dilution of 1:5
(6.5min @ 75F), but when I develop 4x5 sheet Tmax100 in Tmax
developer using my JOBO I use a 1:9 dilution (9.5min @ 75F).
Both methods give the same degree of development, measured
densitometrically (and both used one-shot). If I were to use a
1:5 dilution for 6.5min for the sheet film, I'd get a negative so
overdeveloped that it would be unprintable (unless the scene was
incredibly flat).
b&w prints in JOBO: No. It won't be helpful qualitatively,
and it will certainly slow down your darkroom work.
Good luck.
Mark Gunion
mwgu...@ucdavis.edu
BJCarlton
>developing at 20 Celsius (68F) and prewetting the film for 5
>minutes. This will speed down the development.
I've read about this effect. What causes the slow-down? My understanding
of the long pre-wet is that it dissolves the anti-halation coating. Why
(or how) does it have an effect on the developing?
Barry Carlton
Mark Gunion
processing Tmax100 film in Tmax developer.
First, I made an error in my previous post. What I should have said was,
using dilutions of 1:5 (17%) for 6.5min (35mm, manual agitation), 1:9
(10%) for 5.5 min (4x5, JOBO), and 6% for 11.25min (4x5, JOBO), I get the
same degree of development. I apologize for sending that out incorrectly.
Second, I do agree that the characteristic curve of Tmax100 film processed
in Tmax developer changes as a function of the dilution used, at least in
my hands under the circumstances I just mentioned. But not, I think, in a
manner which changes the tonal renderings appreciably, if at all. In
looking at my densitometric plots of these methods, I see
indistinguishable plots, which closely approach straight lines, from Zone0
through about Zone10. Above these densities, the most dilute solution (6%
in JOBO) starts rolling off fairly quickly, about Zone10 or Zone11. The
17% solution (manual) doesn't start to roll off until Zone14.
Unfortunately, my data for the 10% solution (JOBO) don't go past Zone10,
but at that point the curve shows no signs of starting to roll off.
In answer to the point about stronger dilutions, I have done manual
processing with solutions of 1:4 and even 1:3. These curves are not
_qualitatively_ different from those of the more dilute solutions I have
used, as I have used them; they are _not_ straighter, just steeper.
Whether the same would be true in other circumstances, I don't know.
From this I would conclude that you wouldn't really expect to see any
differences in the tonal renderings of the various methods I have used
that yield N development, since the zones one normally prints seem to be
developed identically. The one exception might be that very bright
objects (high zone numbers, 10+) would be easier to print using negatives
developed in the more dilute solution, since it seems to have something of
a compensating effect; they should require less burning in those areas.
So, that's how things work for me. Again, I apologize for the earlier
error.
Mark Gunion
mwgu...@ucdavis.edu
Guy de Riencourt
longer than if you did no prewet. Jobo says to prewet for 5'00" and tests by Phil Davis on Darkroom & Creative Camera Techniques sh=
owed that times of less than 5'00" give different results. This to say that if you prewet for 5'00" or 10'00" the developper time wi=
ll not need ajustment but if you go from 3'00" to 5'00" you will have to.
I will just throw this comment in here if someone has something to say about it I would be glad to here on it. With Jobo rotation th=
e only developper that gives me problems of too much contrast is HC-110. I have to dilute it very much if I want to use it as a deve=
lopper. I use it only for developping Pan Masking at 30ml of *stock* for 1 liter of total. I never had any problem with TMAX, D76, I=
D-11.
Guy
<deri...@micronet.fr>
Paris, France
John Bray
: A while ago I bought a second hand Jobo processor (CPE 2). I have not
: yet got into colour printing but I plan to. In the meantime, I have used
: it to process my black and white films. I have two questions:
: I use Tmax developer to process my Tmax 100 films. The information given
: about making up solutions is not terribly helpful: I would like to use
: the solutions once and throw them away. What concentration should I use
: in the rotary processor ? (I need 240 ml of solution.)
aleks, i used a cpe2 for a long time for b+w. was very pleased with it.
you don't say what size your film is. it has been my experience that if
you're using a film tank, you can just use the tmax as you've been using it
in your prior method. if you're doing larger films, say like 8x10 in a print
drum, i found that i had to increase from my normal 1:15 dilution to about
1:11 to get reasonable times. that seemed to be a general way to approach
it, based on what jobo usa told me.
: Is there any advantage in processing Multigrade prints in the rotary
: procesor as compared to trays. (I tend to use 8"x10", low volume).
i'd never bother to do any b+w prints in a jobo. their print drums don't do
fiber at all anyhow. stick with your trays.
john
--
john bray - jb...@spd.dsccc.com *or* kb6ql on 15m.
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