Chart for PAPER developing Time/Temperature

[Mahler_one]

Does anyone have a reference to a chart portraying the different time(s) for paper development at temperatures ranging from 68-75 degrees F? Is there a "factor" that one can easily use?

Thanks.

Ed

 

[fschifano]

I haven't seen one, and that's probably because there's no real need for it. Paper is done by inspection, under a safelight, and to completion. Do not attempt to pull a print before it is completely developed in an effort to control density. Do that with careful exposure. Temperature is relatively unimportant under these circumstances. My darkroom can be as cold as 55F in winter, and as warm as 82F in summer. I let my prints develop for a good 2 1/2 minutes no matter the temperature and you can't tell which were made in winter and which were made in summer. Don't worry about it.

 

[Mahler_one]

OK...thanks for the advice. I have no easy way to control the temperature of paper development, hence the question.

 

[Kirk Keyes]

Printing paper is developed to completion, or pretty close to it. As Frank says above, don't try to shorten times too much or you get a whole lot of problems. I develop for 2.5 minutes as well as a rule.

 

[grahamp]

There is a development factor - the ratio of the time it take the shadows to start to appear to the time for complete development - but it does vary with different print developer and paper combinations. On the other hand it is reasonably consistent with temperature variations.

 

[Mahler_one]

Thanks to all...I am doing some standardizing of my paper to determine paper speeds and grades. I have settled on 2 minute devloping time using Dektol, 1 plus 2, but obviously at higher temperatures the 2 minute developing time might be at completion, but at, for example, 68 degrees, two minutes might NOT be at completion. Suggestions? One might simply develop at 2 minutes 30 seconds at ALL temperatures which would, I think bring devleloping to completion.

 

[Nicholas Lindan]

One rule of thumb for developing time/temperature compensation, for 2-3 minute developing times, is 15 seconds for every 2 degrees.

Most fiber paper takes 3 minutes at 68F to develop to completion, RC takes 2 minutes. Paper will develop more if left in longer but normally all that happens is the curve develops a very long shoulder and the shadow detail turns to mud. Warm tone papers can take 4 minutes to develop fully. And some developers, like Ansco 130, are very slow and can take 6 minutes to develop a print.

As developer ages the time to develop to completion lengthens. Figure doubling the developing time for every 48 hours the developer is in a tray. I find partially used developer ages very quickly when returned to a bottle after it has been in a tray for a day.

If you are using old developer it is a good idea to check time to completion - take a few scraps of paper, expose as usual, and pull them from the developer at 30 second intervals.

I use fresh developer for any important work. If you buy the Sulfite and Carbonate at the pool store by the bucket it is very cheap to make up D-72/Dektol. I find the key to happiness with DIY D-72 is the addition of 1/2 tsp EDTA per liter of water when making up the stock solution.

For more information try consulting "Controls in Black and White Photography" by Richard J. Henry.

 

[Mahler_one]

Interesting Nick.....what does the EDTA accomplish?

Ed

 

[Mahler_one]

By the way Nick...I assume that you mean 15 second LESS time for every 2 degrees greater then the baseline temperature, which is????

 

[David A. Goldfarb]

There is a good description of factorial development, which grahamp mentions above, in Ansel Adams' _The Print_. The idea is to be able to compensate on the fly for changes in temperature and exhaustion of the developer over the course of a printing session by maintaining a constant ratio between the time it takes for the image to emerge to the time it takes to complete development.

For instance, when I develop Azo in amidol, the emergence time is about 1/3 the total development time. Adams described using a metronome for factorial development, which I've done, but I usually just leave a timer on and keep track, when I'm working this way. It's also useful to know the emergence time for water bath control, since this is when I'd usually pull the print from the developer and transfer it to the water bath.

 

[Claire Senft]

Unsure am I of what you are looking for. Below you will find a chart that was found in Photo Tech. magazine several years ago that is intended to cover the range of 64ºF to 80ºF while giving an equal amountr of development to b&w photo PAPER with a hinge point of 120 seconds at 68ºF.
In other words it tells you how long to develop your paper to get the same results at any temperature within that range. I have used it for 3 or more years. It works nicely. Unfortunately, I am unable to stop putzing around and to leave well enough alone. I have modified the chart from they way it was originally published. I wish that I could remember the author's name to give credit where it is due. But, alas, a lack of memory has made that information lost. I work in a darkroom that has neither heating or cooling. Seldom does my basement darkroom exceed 80ºF. It is quite common for it to have a temperature lower than what is shown on the chart in the winter. I have, and perhaps am, an electric old crock pot or slow cooker that I use in the winter. It is kept approx. 3/4 full of water. I pour a liter of developer from the paper tray which usually has 1 1/2-2 liters of fluid into a 1 liter stainless film tank, insert it into the water bath and stir it when the temp falls below 64ºF. A minute stirring raises the temperature a very useful amount. I pour the developer back into the tray, read the temp and away I go. Hopeful am I that this chart is as useful to others as it has been for me.


º of F seconds
Temp. of time
64 158
65 147
66 137
67 128
68 120
69 112
70 109
71 98
72 91
73 85
74 80
75 75
76 70
77 65
78 61
79 57
80 53

 

[Mahler_one]

Thanks for going to the effort to post the chart! However, a quick question: Have you noted that the shorter developing times at the higher temperatures evidenced the same DMax as the longer times at 68 degrees? As was noted earlier here, the question is essentially one of developing to "completion". Another question: Suppose one decided to keep things simple, and simply uses two minutes developing regardless of the temperature ( assuming one was working above 68 F ). At the higher temperatures, would the "longer" developing times have any harmful effects on the paper? I read that time in the developer past a certain point can actually degrade the image, but one wonders if one is at such critical time using the chart furnished.

Once more, thanks so very much Claire.

I haven't heard the term "putzing around" for a while now, and I appreciate the colorful language! Really nails what many of us do in the darkroom.


Ed

 

[Lee L]

Interesting data Claire. I didn't see that article. I did plug your numbers into a spreadsheet to find the relationship. I'm 'funny' that way. It appears that your time for 70F should be 105 seconds (not that the 4 seconds difference is that critical). Perhaps a typo?

The rest of the data fits very well to the curve:

Development time in seconds = 12049.01*0.93446^Fahrenheit Temp

This is the same kind of curve seen for film development time vs temp.

Lee

 

[mjk]

I don't think I've EVER timed paper development. I just stick in in the soup and when it looks "done" I take it out. Usually that's about 2 minutes, but if I goofed up exposing the paper, it can be anywhere from about 30 seconds to 4 or so minutes...

 

[MattKing]

I always time my paper development - especially when printing for the postcard exchange.

I wasn't quite so anal when I was working on deadline in newspaper darkrooms (where is that hot and cold water?).

Matt