An excellent point, Gerald.
Originally Posted by Gerald C Koch
Graywolf - I apologize if my post made it sound like it doesn't work, or that you don't know what you're doing. That was not the intent.
Here is a question, if my problem is the temp rise, how come I did not have this problem last summer. I just flipped through my negative file, and the only films doing this are the last two batches. The range of temps on all that film was probably from 60f to 80f (Occasionally, the temps get beyond what the electric heat, or the little window AC can deal with.), but as I said, this has only happened on the last two batches (one roll, and two rolls, respectively).
I will take that back, the last batch of 4x5 was messed up too. Only, I know why that was, I had changed my technique. Which is why I went to following a written procedure, so I will do it exactly the same way each time.
No, temperature is not the problem. Once equilibrium is reached there it not much transfer of chemicals in and out of the emulsion, especially with highly dilute systems. My whole semi-archival rinse is based up on that fact. I guess I am going to have to go through the hard headed process of trouble shooting my procedure, because something has changed, and I am not seeing what that is.
Thanks, everyone, for your comments.
Well, if everything regarding temperature is always different but your results are usually the same, then maybe you got a hot batch of film. The only way you're going to pin down the variable is to test it at a consistent exposure, temperature, time, and agitation method. If Arista EDU film is Fomapan, it would not be out of the realm of possibility that there is some inconsistency between emulsion batches. Buying film from a major manufacturer is another way to help insure consistency.
I can buy that idea, Peter. I have some Fomapan 100 that was gifted to me, and it does not come out exactly the same as the Arista. Even the film base does not seem to be exactly the same, the Fomapan curls more. I will check my remaining film to see if it is from different batches.
One thing that occurred to me is that I recently put up a vent fan in the bathroom, but I checked with a dish of water and it does not seem to be inducing any vibration to the sink counter where I set the developing tank. So, I will have to look for something else.
I use bottled distilled water in my chemical mixes, so I do not think the problem is the water. We are on a well here, and if I was using tap water, who knows what may have changed.
The weather here has been higher than normal, but I can not see how the outside ambient temperature could change things.
One of the things I remember from my history of photography studies long ago. Kodak had a batch of film come out 4 times as fast as the previous batches (in the 1800's, IIRC). They did extensive investigation and found out that the gelatin came from cows that had been pastured where there was some wide mustard plants. Turned out that something like (remember, is this from memory) 2 parts per billion of oil of mustard in the emulsion accounted for that increase in speed. The point here is that it does not take a lot to make big changes. This is a good reminder, I may not be able to figure out just what is causing the change, as I have no way of detecting changes that small.
The interesting thing is that my method of developing had been giving me almost exactly box speed on this film, when most folks claim it is slower than that. Now, it looks like I am getting about 2x box speed. Humm...? Could they have packaged some Fomapan 200 in the Arista 100 boxes?
I just looked at those negatives again to check the edge printing, they are edge printed "Ultra 100".
So you're willing to consider changes in the diet of a cow but not your stated 10 degree temperature shift...?
Originally Posted by graywolf
Like a 10 degree temperature shift...
Originally Posted by graywolf
I'm sorry to keep beating the temperature drum, I simply think it's worth revisiting this. People here much more knowledgeable than myself seem to think that's the root of your problem.
I hope you get this figured out, graywolf. I know how frustrating film development problems can be.
All the best.
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Anset Adams in The Negative (fourth printing) describes stand development and gives a specific temperature and time in his example for the process. So he did not consider stand development to be independant of temperature.
According to Boltzmann the speed of any chemical process doubles for each 10 oC rise in temperature.
Last edited by Gerald C Koch; 07-25-2012 at 05:59 PM. Click to view previous post history.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.
~Antoine de Saint-Exupery
I knew someone with engineering/chemistry/physics knowledge would have a handle on the thermodynamics of the temperature increase! So, in layman's terms, if your developer is really only, say, 50% dead at the end of 60 minutes at 65F, it's going to be way overcooked at 75 degrees.
In practical terms, a simple test would answer the OP's question. Put identical film in identical developer, one at 65F, the other at 75F, and let them stand for
an hour. Compare.
Well, I think I may have found the problem.
I was having a midnight snack last night when all of a sudden all the dishes in the cupboards started rattling. I do not know what the neighbors were doing that caused that, but the bathroom/darkroom is directly above the kitchen, so if it was making the kitchen vibrate, it most likely was making the bathroom/darkroom vibrate too.
Said vibration would, of course, cause agitation of the chemicals. I will try putting the developing tank on a foam rubber pad next time. I will continue to report until I have solved this problem for sure, or I have given up; don't you hate people who ask interesting questions, then do not follow up with what they have found out?
I see that some people are still arguing that what they have read is more true and accurate than my real world experience. That does prove something...
Yes, it proves that many here are stubborn and willing to lay their reputation on the line to try to help you solve your problem. They are just as convinced about their solution as you are about yours.
Originally Posted by graywolf
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh
If Rodinal then 1+100 for an hour @20°C +/- 1°C.
500ml +5ml. If you have small tank pour to fill the tank then one tap at the bottom to dislodge the bubbles.
I have no experience with other volumes or temps.
OM-1n: Do I need to own a Leica?
Rolleicord Va: Humble.
Holga 120GFN: Amazingly simple yet it produces outstanding negatives to print.