[pure-silver] Re: TMax 100 - developing info discrepancies
- From: Alfonso Gorostiza <arrillaga@xxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Mon, 18 Sep 2006 12:09:09 +0200
Hi all,
I'm not a big poster, I'm learning yet, but I can give some advice
(coming from other sources).
You could try the test I explain below and see which developing time
(from Kodak or from the Massive Dev. Chart) fits better.
Cheers
Alfonso
JC> I have a few rolls of TMax 100 to process, but I've found conflicting
JC> info. The Massive Developing Chart says to give it 9.5 min. in D76,
JC> 1:1. Kodak says 12 minutes. That's a big difference. Should I
JC> safely assume Kodak's time is the right starting place? Thank you.
The other day I found a test to calculate the developing times for any
film-developer combination. The test is very old but very reliable and
very useful for cases like this one, when there is a very old film, or
when the developer is not known (how exhausted it is, temperature,
etc).
The test is as follows:
1.- Get the rebate of the film that has to be developed. The rebate has
to be exposed, as it is the film lead out of the cartridge.
2.- Under heavy light, or at least powerful enough, with a glass bar
or the thermometer, take the biggest possible drip of developer and
place it on the film and start counting the time.
3.- Watching carefully, we will see that the film density under the
drop starts to be clearer than the surrounding area. After some
seconds, that clearer area starts to recover the density.
4.- As the time is passing (something between 25 and 70 seconds) we
have achieved the critical phase: the "under the drop" film gets the
same density than the film not affected by the developer and, after 2
or 3 seconds, when it gets more density, just enough to be
distinguished. In this precise instant we have to stop or watch.
5.- If we divide this time (IN SECONDS) by 4 we will get the
developing time IN MINUTES for this film-developer combo at this
temperature.
This test, called the drop test, is over 100 years old, and what we
have done is, basically, to calculate the minimum developing time for
the high lights. It is very important to do the test with the film
already in the tank and develop immediately after the test. It is also
very important not to handle the film rebate too much as grease
deposits could alter the test. If, after the test, you are not very
sure when the density has started to be higher than the initial one,
you could repeat the test in the same rebate. With very diluted
developers, this test could be less reliable, as the developer could
get exhausted due to the small size of the drop. In a case like this,
the density variation is better seen in the drop edges. For 120, 220,
127 films, you have to cut a rebate when loading the film in the reel,
of course in complete darkness and expose it afterwards.
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