Hi Raymond,

Thanks for your reply and advice.
Please find further comments inline.

--- In black-white-photography@yahoogroups.com, "Raymond Copley"
<raycop@...> wrote:
...
> You did not state what film you were using or the exposure setting.

Have a look at my original post
<http://tech.groups.yahoo.com/group/black-white-photography/message/1814\
> , it's all there: Efke IR820c, two sheets intentionally exposed
through an R72 filter after metering at 1 ISO, one sheet (sheet #2)
accidentally exposed at 1 ISO without the filter.

> Slow speed films (32-64 ISO) require shorter processing times because
the emulsion is thinner and therefore requires less developer activity.
The time increases when faster films (thicker emulsions) are used.

Information about this film is spotty, but it seems that for visible
light it would be rated between 100-200 ISO.

> When using a developer for the first time, process a short length of
film in full strength developer at the manufacturer's recommended time
and temperature. Ilford provide a simple chart to calculate time and
temperature above and below the recommended combination at 20C. and the
recommended speed settings (ISO) for each category of emulsion (slow,
medium & fast).

Unfortunately, for this film there is no such thing as a manufacturer's
recommended time, or at least I could not find such a thing. So I
checked with the giant devchart <http://digitaltruth.com/devchart.html>
. As I said earlier, I have Microphen available and the chart lists one
time for it: 7 minutes with stock solution. However I knew that I would
have to use drastically reduced processing for the overexposed sheet,
and times were getting very short anyway at the temperatures I had to
deal with, so I decided to go with 1+3 and a longer time to start with.
Seems I did not choose that time long enough, so I ended up learning
something!

> Careful assessment of negatives from this initial test will enable you
to competently adjust film speed and processing time to suit your camera
and exposure techique and your processing methods. These vary from one
person and set of equipment to another.

Yes, that's what I'm just getting started with and originally asked for
advice on. As none was forthcoming I then started to do my own
experiments.

> Always remember that there is NO single combination to suit every
situation. If this is what you want, then use auto digital, not wet film
processing. The former delivers wonderful images, the latter is an art
form which for 150 years has been producing fantastic results. Some
people use both methods suit their particular needs.

Not sure what you are trying to tell me here, Raymond. [:)]
I've been reporting on my progress with trying to work out proper
exposure and development for Efke IR820c sheet film as well as my
attempt to salvage a sheet that was accidentally overexposed. And asking
for advice about either - no need to threaten one of the few remaining
film-users at the MCC with the digital hammer! [;)]

> During hot weather, running tap water usually doesn't get above about
23C..

Well last night it did, and I had it running for quite a bit but could
not get the temperature much below 30C.

> If solutions are appreciably higher, place them in a refrigerator for
a few minutes. Let the temperature drop to about 18-19C.; it will rise a
degree or two during development (the crtical temperature) and should be
"about correct" when averaged over 10 minutes. The fixer temperature is
not critical, but shouldn't be below about 16C. or 5C. different from
the developer temperature as this may cause a visible change in grain
sharpness.

Ok, I didn't think of the fridge in the Club's kitchen. Would've taken
more than just a few minutes to cool the stuff from 30 to 18C, but good
idea anyway.

> Film development is a strict but simple scientific process if the best
results are desired. Treat it as such, whether you are processing in a
well-equipped darkroom or on the kitchen sink. I have used both
locations on frequent occasions with equal success (and some failures
through not sticking to the rules!)

Ok, then what next step would science suggest to take from here?

My suggestion was to expose a bit more (for 0.75 ISO instead of 1 ISO),
going from the examples referred to in my original post, which look good
to me, and the comments posted with them (there's not just the one image
but a whole album). Does that seem about right?

I could go out and shoot four to six sheets of the same subject and with
identical settings, so that I can concentrate on getting the development
right.

Then cool my chemistry to 18C and process about 50% longer (after
compensating for temperature) than I had done so far, to get reasonable
density. Because development time at 1+3 would become about half an hour
(at 20C) I thought of using 1+1 with an appropriately shorter time (ca.
20 minutes as a starting point).
You say I should start with stock solution - I can try that as well,
what time would you suggest as a starting point?
Or should I use a different developer altogether, what do you think?

Any and all suggestions appreciated.

Many thanks for your input & best regards,

Ronald



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