Temperature Controlling - Color Printing

[Sheheryar Hasnain]

Hi
I will be decending into the world of Radiance and R-3000
in the next few days. I needed to know how all of you
color print makers control temperatures without expensive
(or any) equipment. I'm not sure what R-3000 has to be
maintained at (I assume in the 90s somewhere), the first
developer that is. But I heard of a way where you "heat
the drum" by an initial rinse at a particular temperature
and pour in the first developer at room temperature. Apparently
it adjusts to the right temperature. Have any of you
tried this? There is some table for temperature and time
of the first rinse which I would appreciate someone sending
to me. However I would like to hear you on how you
maintain the exact temperature for the first developer.
What is a good "soak" temperature for the bottles of chemicals
to keep at so they stabilize at the correct temperature. Since I
dont know the temperature I am looking at, a general formula
would be helpful. Any advice would be appreciated.
Thanks.
Sheheryar

[Thorn Roby]

I use a method similar to what you describe for EP2 processing. It may
be less sensitive to temp variations than R3000. For a nominal 100
degree process, in a 68 degree room, I typically preheat 12 ounces of
solution to 110 degrees, and use two 110 degree prewashes in a 16x20
Jobo tube. I have never really tried to figure out what the exit temp
of the solutions is - I just try to be reasonably consistent from
batch to batch. You could probably get a pretty accurate idea of the
nature of the temp drop by testing with plain water and pouring out
at one minute intervals into a styrofoam cup with a thermometer. I avoid
water baths when possible because they're one more thing to maintain,
and I've had problems with contamination of solutions. You might want
to put a scrap print in the tube when testing, as it would probably have
some effect on the temp characteristics, as well as the amount of
solution retained in each step.

I do it this way because I reuse the large volume of solution, which is
economical and I feel the larger volume improves the temperature
stability and coverage of the procedure. If you're stuck with a one-shot
small volume (e.g. 4 ounce) process, you will probably need to adjust
the starting temperature upwards. In any case, I'd recommend a large
volume for the preheat water.

In other circumstances I've resorted to more extreme measures such as
shining an infra-red lamp on the tube and drilling a hole in the tube
to leave a thermometer in place. The Radio Shack indoor-outdoor
thermometers with a flexible probe can be useful in some circumstances,
although they take about thirty seconds to settle on a reading. Probably
difficult to insert into a rotating drum, though. Be sure to calibrate
against a trusted thermometer at the working temp - I think they're
not particularly accurate, but their error seems pretty consistent.
--

Thorn Roby tr...@diana.cair.du.edu
CARL Systems, Inc. tr...@carl.org
3801 E. Florida Ave.,Suite 300, Denver, CO 80210 (303) 758-3030

[Barry Sherman]

What you're talking about is called "drift-by". By warming the tube to
above the processing temperature just the right amount you'll get the
developer to the corect temperture when it's poured. It'll immediately
start to drop and will drop noticibly during the several minutes of the
developing step. The amount of the temperature drop will vary with the
ambient temperature. Most people who I've heard of using this technique
check on how much the temperature drops during a "simulated run" at the start
of each session and adjust starting temperatures accordingly. I suspect that
day-to-day repeatability of results cannot be very good using this method.

There is a simpler, although somewhat more (inexpensive) gear-intensive way of
maintaining temperatures:

1) Get yourself a decent darkroom thermometer. This will be essential ]
regardless of the technique uses. If you pay less than $20 you're not
getting anything worth having.

2) Make sure that the processing drum is the type which has a water-tight
lid. Jobo's come immediately to mind.

3) Get two Rubbermaid or Tupperware or similar basins. ONe will be long
enough for the drum to rest in it horizontally. The other should be
large enough to hold your containers of chemistry.

4) Buy a sheet of 1/2 inch or so expanded polystyrene (styrofoam). I under-
stand that this is now being made without CFC's so you'll not be committing
a gross environmental sin by doing so.

5) Using a serrated edge kitchen knife cut the styrofoam to size to fit on
each side of each basin, including the bottom. Now glue the pieces of
styrofoam to the basins using silicone caulk. Cut a piece of a size
to fit over the top of each basin and cut holes in the one for the bath
to be used for the chemistry such that the chemistry bottles can be
inserted and removed.

You now have two insulated water baths which will hold temperatures amazingly.
I used mine for processing before I got my Jobo and still use them for holding
rinse water for the Jobo. I doubt that you've spent more than $15, if that.

6) Fill up each bath with water of the correct temperature.

7) Use the microwave to heat the bottles of chemistry to the right
temperature. (I find the microwave to be one of the most useful darkroom
tools around.) (Along with the freezer for cooling b/w chemistry on hot
days.)

8) 15 minutes of sitting in the tempering baths should bring the chemistry
to nearly the correct temperature. You may need to add a little hot
water to the baths during this interval in order to maintain exactly the
correct temperature.

9) Process, using the water-tight lid on the drum so that you can float
it in its water bath while rolling it. This is pretty much a jury-rigged
Jobo and I found it to work just fine for doing Cibachrome before I got
my Jobo.

Barry
--

|----------------------------------------------------------------------------|
| Barry Sherman, Amdahl Corp. | "It's much easier to go to exotic places and |
| b...@uts.ccc.amdahl.com | capture spectacular scenes than to take a |
| | spectacular picture of a really boring |
| | green pepper". - Anthony Tse |
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| Amdahl, being a corporation, is a legal fiction. Therefore it is incapable|
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| said of me as well. (I.e. My statments are mine, not Amdahl's.) |
|----------------------------------------------------------------------------|

[Herbert Kanner]

Drift-through processing is not as uncertain as Barry implies. The
procedure is: Keep your chemicals at the nominal processing
temperature in a water bath. Preheat the drum/paper with 250 ml. of
water at a higher temperature gleaned from a table (or determined
experimentally--more about this later). Granted, the preheat
temperature depends on room temperature, but it is a very weak
dependence.

Try the ChromeR kit by PhotoColour (British, imported by Jobo) Their
instructions have a fairly rational discussion of drift-through
processing. I have made a few prints with Radiance and perhaps a
hundred with the predecessors, Ektachrome 14 and Ektachrome 22. I find
that temperature control is not as critical as most people have been
led to believe. Another alternative is the Unicolor 3-step kit. I
don't know how they did it, but that kit works in a reasonable time at
room temperature. Most of my earlier work was with that kit, but I
have switched to the PhotoColour line because of greater availability.

A Mickey Mouse way of controlling the temperature of a water bath that
is open to the air has been working for me. I wired a one-cup
immersion heater (the sort of thing you use for brewing a single cup
of coffee) in series with a dimmer switch. It does not take to long to
find a setting of the dimmer switch which will cause the bath to hold
the desired temperature.

Good luck--it's easier than you think.
--
Herb Kanner
Apple Computer, Inc.
{idi, nsc}!apple!kanner
kan...@apple.com

[Alan Dick]

One suggestion (perhaps improvement) to the setup Barry described using
Rubbermaid containers with insulating foam on top is to add a cheap fishtank
heater to the setup. I did my color printing this way for 2 years before
I got my Jobo. The heaters are designed to be immersed
in water and have adjustable thermostats. One warning though. Buy a cheap
heater not an expensive one. The expensive ones I have tried have been
calibrated to not go above about 95 degrees (least you boil your fish),
however, I bought a cheap one a K-Mart (< $8) which worked fine.

Alan

[donl mathis]

In article <C7p2y...@acsu.buffalo.edu>, MGT...@ubvm.cc.buffalo.edu

If you have a way to slosh the water around in the bath, also, it will
help keep things a bit more even. If it just sits, it will get warm
around the heater and that's it. It seems like a boat paddle would
work, but it might be too big. Maybe a hand would work. Maybe a
little pump would work, with no manual effort.

I used to use two aquarium heaters, in hopes of keeping things a bit
more even. I suppose the theory was that their thermostatic errors
would sort of average out.

- donl mathis at Silicon Graphics Computer Systems, Mountain View, CA
do...@sgi.com