Adjusting development for temperature

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)?

An experiment with a roll of film at 1.66x recommended time yielded a
rather razor thin negative, though the film had been sitting in the
camera a year or so. This time factor was taken from an old Manual of
Photography by Focal Press, but it was not specific to D76, just part
of a table of suggested factors at a given "temperature coefficient".
The Manual refers to temperature coefficient for developing agents and
listed a table of factors for a coefficient of 2.75. Here is a part of
the table:

Temp: Factor
15 deg C: 1.66
17 deg C: 1.35
20 deg C: 1.00
22 deg C: 0.82

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?

Some further searching on Google found the following link with some
more details:

"A characteristic, named the "temperature coefficient," has been used
as the quantitative measure of the change of activity. This is defined
as the ratio of
the development times required to produce equal density at two
temperatures differing
by 10°C., which is, of course, a difference of 18°F. The values
obtained range from 1.3 for metol alone, through 1.9 for pyro and
metol-hydroquinone combinations, to 2.5 for glycine."
from: http://www.questia.com/PM.qst?a=o&d=97634617
(in referernce to the book: Handbook of Photography by Keith Henney,
Beverly Dudley; Whittlesey House, 1939.)

Thanks for any comments.

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

wrote in message
...
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)?

An experiment with a roll of film at 1.66x recommended time
yielded a
rather razor thin negative, though the film had been sitting
in the
camera a year or so. This time factor was taken from an old
Manual of
Photography by Focal Press, but it was not specific to D76,
just part
of a table of suggested factors at a given "temperature
coefficient".
The Manual refers to temperature coefficient for developing
agents and
listed a table of factors for a coefficient of 2.75. Here is
a part of
the table:

Temp: Factor
15 deg C: 1.66
17 deg C: 1.35
20 deg C: 1.00
22 deg C: 0.82

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?

Some further searching on Google found the following link
with some
more details:

"A characteristic, named the "temperature coefficient," has
been used
as the quantitative measure of the change of activity. This
is defined
as the ratio of
the development times required to produce equal density at
two
temperatures differing
by 10°C., which is, of course, a difference of 18°F. The
values
obtained range from 1.3 for metol alone, through 1.9 for
pyro and
metol-hydroquinone combinations, to 2.5 for glycine."
from: http://www.questia.com/PM.qst?a=o&d=97634617
(in referernce to the book: Handbook of Photography by
Keith Henney,
Beverly Dudley; Whittlesey House, 1939.)

Thanks for any comments.

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. If you are not using a Kodak
film you can still get pretty good estimates from this data.
I think Ilford has similar information on their film data
sheets. The variation for D-76 and Ilford ID-11 should be
very much the same although the packaged developers are not
quite identical.


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

"Andrew Price" wrote in message
...
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

And keep your fingers crossed and hope by chance the chart is right. Many of
them are just straight-line extrapolations and that is not how all chemistry
works. Some of their film development specs are flat out guesses, some upon
a recommendation of a quesitonable source. One of those sources is a
hairbrained maniac who frequented this place and hasn't developed a roll of
film for forty years. Pure impressionism.

In article ,
Richard Knoppow wrote:

wrote in message
...
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)?

An experiment with a roll of film at 1.66x recommended time
yielded a
rather razor thin negative, though the film had been sitting
in the
camera a year or so. This time factor was taken from an old
Manual of
Photography by Focal Press, but it was not specific to D76,
just part
of a table of suggested factors at a given "temperature
coefficient".
The Manual refers to temperature coefficient for developing
agents and
listed a table of factors for a coefficient of 2.75. Here is
a part of
the table:

Temp: Factor
15 deg C: 1.66
17 deg C: 1.35
20 deg C: 1.00
22 deg C: 0.82

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?

Some further searching on Google found the following link
with some
more details:

"A characteristic, named the "temperature coefficient," has
been used
as the quantitative measure of the change of activity. This
is defined
as the ratio of
the development times required to produce equal density at
two
temperatures differing
by 10°C., which is, of course, a difference of 18°F. The
values
obtained range from 1.3 for metol alone, through 1.9 for
pyro and
metol-hydroquinone combinations, to 2.5 for glycine."
from: http://www.questia.com/PM.qst?a=o&d=97634617
(in referernce to the book: Handbook of Photography by
Keith Henney,
Beverly Dudley; Whittlesey House, 1939.)

Thanks for any comments.

The temperature coefficient varies with the developer
and to some degree with the film so there is no absolute
rule.

How about "there is no coefficient"? These are not simple first-order
functions.

--
Thor Lancelot Simon

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

In article ,
Richard Knoppow wrote:

The temperature coefficient varies with the developer
and to some degree with the film so there is no absolute
rule.

How about "there is no coefficient"? These are not simple first-order
functions.

--
Thor Lancelot Simon

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

--
Thor Lancelot Simon

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

In article ,
Richard Knoppow wrote:

The temperature coefficient varies with the developer
and to some degree with the film so there is no absolute
rule.

How about "there is no coefficient"? These are not first-order
functions.

--
Thor Lancelot Simon

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

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

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).

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.

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).

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.

Many of
them are just straight-line extrapolations and that is not how all chemistry
works.

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.

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?

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.

Pure impressionism.

Indeed - but whose?