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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. |
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Adjusting development for temperature
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#3
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Adjusting development for temperature
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 |
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Adjusting development for temperature
"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. |
#5
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Adjusting development for temperature
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 |
#6
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Adjusting development for temperature
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 |
#7
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Adjusting development for temperature
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 |
#8
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Adjusting development for temperature
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 |
#9
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Adjusting development for temperature
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). |
#10
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Adjusting development for temperature
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? |
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