Adjusting development for temperature

"Andrew Price" wrote in message
...
On Sun, 6 Apr 2008 18:26:09 -0500, Pico wrote:

and then compensate for the actual temperature of your basement, using
their time/temperature chart:

http://www.digitaltruth.com/images/time.gif

And keep your fingers crossed and hope by chance the chart is right.

It's a starting point, nothing more. Most people who are seriously
interested in developing their own film take notes and compare the
results at different temperatures and dilutions.

It may be a stopping point. If the full chemistry isn't active at 60F,
nothing might happen.

But over the short temperature range quoted (+14 to +24) it is a
starting point, and one recommended by Ilford and other manufacturers
of black and white film.

Bull****. Those are the recommended ranges, bottom and top, not higher and
not lower than that range.

Some of their film development specs are flat out guesses,

Hmm... supporting data?

some upon
a recommendation of a quesitonable source.

Do you have any convincing supporting evidence of that assertion?

I would, but I forgot the guy's name. Spanky or something like Uranium
Committee. Yep, that's a pseudo he used. Search for 'dougnut boy', his
lifelong masterpiece done in high school fifty years ago.

One of those sources is a
hairbrained maniac who frequented this place and hasn't developed a roll
of
film for forty years.

Being more specific would add credulity to that statement.

I wrote that I would if I could recall his name, but some things are worth
forgetting. I don't know how long you have been around, and I don't want to
bother looking, but you might remember if you ... wait, It is Michael
something.

Pure impressionism.

Indeed - but whose?

Michael S (spook, spoor, smegma, something)

On 4/7/2008 5:43 PM jjs spake thus:

"Andrew Price" wrote in message
...

Do you have any convincing supporting evidence of that assertion?

I would, but I forgot the guy's name. Spanky or something like Uranium
Committee. Yep, that's a pseudo he used. Search for 'dougnut boy', his
lifelong masterpiece done in high school fifty years ago.

Close; you're talking about (dare I invoke his name here, lest he come
back to torment us?) Michael Scarpitti, aka "Uranium Committee" aka
"Waffle Boy".


--
The best argument against democracy is a five-minute
conversation with the average voter.

- Attributed to Winston Churchill

"David Nebenzahl" wrote in message
s.com...

Close; you're talking about (dare I invoke his name here, lest he come
back to torment us?) Michael Scarpitti, aka "Uranium Committee" aka
"Waffle Boy".

Yeah, that's the name! He's the guy who claims that Agfa Brovira was overly
contrasty and he could never get a good print. (Its grades were about one
lower than Kodak, back when they both made graded paper, and Agfa went from
0 to 6.) He also claimed that the Leica was the best camera in the world,
and the ****amat enlarging lenses were the very best, and that photography
could not possibly be an art. Didn't he rename his masterpiece to Doughnut
Boy? Or is that his new moniker?

Anyway, he claimed to be an authority on B&W film development and his
recommendation(s) were in Digital Truth. Be suspicious of ANYTHING that says
it is the truth.

Anyway, OP, so develop some Tri-X 125 in 60F or colder water and let us know
how it goes for you. Or don't. I would choose a more active developer for
cold water, something recommended for such an application. But WTF do I
know? I just started taking picture and making wet prints FIFTY years ago.

My next post will be more to the point of the post. Cold development
solutions (no pun).

OK, I don't have the reference book for cold weather processing on-hand. It
must be in storage. Leitz had good information in one of their earlier
books. I might find it this weekend.

In the meantime, an *authoritative source mentions the rule of thumb
mentioned earlier - quoting from the book, "a general rule of thumb for the
range of 65 to 95F is that a decrease of 10F increases the development time
1.5 times." and they mention that the rule of thumb is just that - am
approximation.

Note that they do not include temperatures below 65F because lower
temperature solutions have more profound differences; they are not covered
by the rule of thumb.

* source: SPSE Handbook of Photographic Science and Engineering
1,416 pages

On Apr 7, 4:49*am, Peter wrote:
On Apr 6, 9:46*pm, wrote:

Given that the basement is still coolish from the winter, what would
be the best development time factor for D76 at 60 deg F (15 deg C)?

....

Thanks for any comments.

You have mentioned a number of points of uncertainty:
long hiatus
old film
long time since exposure

You haven't mentioned much about the rest of your technique (e.g., how
sure are you that you used the correct exposure allowing for old film
& etc., why not keep the solutions in a warm room, load the film in a
tank in your dark room and develop the film at a more convenient
temperature in a warm room, how accurated is your time keeping,
temperature measurement and how consistently correct are the solutions
& etc).

A digital timer is being used, with lap times for each step in the
processing. A review of the split times shows that draining the old
tank being used is taking longer than expected, but longer time is not
the problem here. It is possible that the film being at room
temperature for over a year was a factor. The latest roll turned out
with good density. More later.

Personally, I've had poor experience with Plus-x in D-76 at cold
temperatures. *I settled on never developing it below 65F. *That was
decades ago and I forget the details. *Perhaps I was wrong.

Given that the Kodak datasheets do not go below 65 deg F, this might
well be the case.

Even so, you need to prove you can get a correctly exposed roll of
your old film developed to normal density and contrast. *To do this, I
thing you need to plan on trying more than one roll of test pictures
(sheet film is an attractive alternative for such experiments, if
available).

Getting a good roll done was a priority for me, too. A heater in a
small area took the temperature of the chemicals up to 22 deg C over
the course of the day and processing on another roll was done at that
temperature. This time, D76 at 1:1 dilution was used, and the results
look good.

There is a certain satisfaction in the process of developing film,
sight unseen for most of the processing, and finally seeing the
results turn out well.

wrote in message
...
On Apr 6, 5:38 pm, Andrew Price wrote:
On Sun, 6 Apr 2008 12:46:05 -0700 (PDT),

wrote:

[---]

I am just getting back into B&W film again, after a long
hiatus. Any
comments on an appropriate development time for the next
roll?

Check the times for the specific film you're using at:

http://www.digitaltruth.com/devchart.html

and then compensate for the actual temperature of your
basement, using
their time/temperature chart:

http://www.digitaltruth.com/images/time.gif


Thanks. This chart is similar to the values in the table,
but maybe
using a different temperature coefficient? As you can see,
the
temperature scale is linear while the time scale is
logarithmic.
Perhaps the temperature coefficient is the slope of the
line.

Richard Knoppow wrote:
The temperature coefficient varies with the developer
and to some degree with the film so there is no absolute
rule. For some guidance check Kodak film data sheets. Most
have graphs showing the variation of development time with
temperature as well as showing development times for
various
temperatures on the charts.
...

Why didn't I think of looking there? The film I am using
has been
discontinued a few years (stored in the freezer meanwhile).
The chart
for Plus-X only goes down to 65 deg F, though. Maybe Kodak
does not
recommend processing at low temps? Thanks, anyway.

Plus-X tech sheet:
http://www.kodak.com/global/en/profe...18/f4018.jhtml

65F used to be the "standard" temperature up to the
early 1940's when it was increased to 68F due to better
emulsion hardening in manuacture. Much below this one
encounters problems due to hydroquinone loosing activity,
but that depends on the pH of the developer. Low temperature
development is possible and Kodak used to have a brochure on
how to do it.
The simple chemical rules for the variation of rates of
reaction due to temperature and concentration do not always
apply directly to actual photographic processes because they
are complex. For instance, development and fixing are
affected by the diffusion rate into the emulsion which is
partly dependant on temperature but depends on the history
of the gelatin so its not simple.
Kodak appears not to recommend using some developers
below relatively high temperatures, for instance diluted
T-Max. In some of the older Kodak charts a preferred
temperature was indicated by printing the temp in bold type.
This was around 75F for T-Max and some others. Kodak never
stated the reason for this but, usually, they had good
reasons.
I've found that Kodak's data is usually quite accurate
although they occasionally blunder.

--
---
Richard Knoppow
Los Angeles, CA, USA

"jjs" wrote

"a general rule of thumb for the range of 65 to 95F is that a decrease of
10F increases the development time 1.5 times."

Leading back to first-year chemistry ...
http://en.wikipedia.org/wiki/Arrhenius_equation
where the rate of a reaction doubles every 10C.

A variation on the universal equation:

Something = Something Else * e ^ -(Energy of the thing / k * T)

Where k is Boltzman's constant and T is temperature
relative to absolute zero.

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/index2.htm
n o lindan at ix dot netcom dot com

In article ,
Nicholas O. Lindan wrote:
"jjs" wrote

"a general rule of thumb for the range of 65 to 95F is that a decrease of
10F increases the development time 1.5 times."

Leading back to first-year chemistry ...
http://en.wikipedia.org/wiki/Arrhenius_equation
where the rate of a reaction doubles every 10C.

A variation on the universal equation:

Something = Something Else * e ^ -(Energy of the thing / k * T)

Where k is Boltzman's constant and T is temperature
relative to absolute zero.

Unfortunately, there are several reactions going on at once in a typical
photographic development bath. For example, consider a tank full of D76:
the primary development agent (the metol) is being exhausted by developing
the film, and regenerated by stealing electrons from the other developing
agents. A buffer reaction is keeping the pH of the solution stable, at
the same time. More complex developers will have sequestering agents
grabbing up development-inhibiting reaction products and holding them in
solution, etc. -- and all these reactions have different energies, thus
proceed at different rates. Get below or above some threshold temperature,
and the overall reaction won't run as designed, period, and the
characteristic curve of the resulting negatives will be...different.

In any event, if you actually fit curves to the time/temperature data for
common films and developers (at some constant exposure and density) you
will find that they are, at least, shallow 2nd-order curves -- not linear.
And that's within a fairly narrow temperature range, all bets are off once
you get outside there. The film/developer testing page on Paul Butzi's
site has some nice examples of the data and the curves that fit it, and
they are *not* straight lines.

--
Thor Lancelot Simon

"The inconsistency is startling, though admittedly, if consistency is to
be abandoned or transcended, there is no problem." - Noam Chomsky

"Nicholas O. Lindan" wrote in message
...
"jjs" wrote

"a general rule of thumb for the range of 65 to 95F is that a decrease of
10F increases the development time 1.5 times."

Leading back to first-year chemistry ...
http://en.wikipedia.org/wiki/Arrhenius_equation
where the rate of a reaction doubles every 10C.

Perhaps for quite similar chemicals separately, but our developers are
complex mixes.

On Apr 7, 11:04*pm, "jjs" wrote:
...
Anyway, OP, so develop some Tri-X 125 in 60F or colder water and let us know
how it goes for you. Or don't. I would choose a more active developer for
cold water, something recommended for such an application. But WTF do I
know? I just started taking picture and making wet prints FIFTY years ago.

My next post will be more to the point of the post. Cold development
solutions (no pun).

Hi, JJS. Did you have any recommendations for cold water processing?
A check of the Manual I have shows no specific cold water
formulations. However, it did list a tropical developer that can be
used to 32 deg C, useful for when summer comes.