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Extrapolating temperature on film development

tkamiya

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I have a potential need to develop film at temperatures higher than what the highest temp manufacture's chart specifies. I'd like to get opinions and experiences on something like this:

The film is Tmax 400 and the developer is XTOL 1:1 dilution.

The chart on Kodak's literature F-4043 has a chart that goes up from 65F to 75F. I calculated delta TIME over delta TEMP for every increment and arrived at a curve.

65 - 68 30.0sec/degreeF
68 - 70 22.5sec/degreeF
70 - 72 22.5sec/degreeF
72 - 75 15.0sec/degreeF

Obviously, the change isn't linear. What I would like to know is, how far can I take this upward and at what rate? Ideally, I would like to extrapolate this up to 80F but that may be stretching it.

Would anyone have any data or experience? Is there such limitation that above certain temp, things start to break down?
 
The general consensus is that you shouldn't go much above 24 C, or any shorter development time than about 4 minutes. 80 F is nearly 27 C, so that is possibly getting too high.
 
What generated this consensus? What was the chemistry behind it?

My (non-photographic) experience leads me to believe that the sort of chemistry that we are discussing should be able to go to high temps without too much trouble. It is non-enzymatic, so no worries about denaturing enzymes.

I could imagine that materials (film, emulsion, paper composition) might be negatively effected, but the chemistry itself should be able to deal with quite high temps.

Being a newb, I'm sure I've missed a lot of this sort of conversation.

MolBasser
 
Well... One story I've heard is that at higher temps (80F was mentioned), gelatin layer of the film becomes too soft and fragile - increasing the potential to damage. I also heard, modern films are far more tolerant. So there is more than pure chemistry involved. But, being a newbie myself, I don't know the exact limit other than what I've heard over the years. I would love to get story from modern experience or knowledge. Hence my question above.

In central Florida that I live, higher ambient temp is a real problem. During summer time, an area I use for photographic processing easily hits 85F. Even if I use water bath, during my printing session, if I try to keep the temp of water bath too low, (meaning delta being high) it will rapidly increase approaching the room temp. Even now, it can hit 80F which is higher than the factory data sheet goes to.
 
Awesome. I assume there is a ton of published data on the subject then.

Is there an online resource to access said data?

Or is it a collection of anecdotes?

Not trying to be a jerk, just looking for a collection of data to work off of. Why are high temps bad? Media issues (gelatin/paper/film)? I can't imagine the relatively small ranges of temps we are talking about have to do with the physical chemistry.

MolBasser
 
My opologies, as that last post reads pretty poorly.

I'm still interested in the science behind the ideas though.

MolBasser
 
At 24 degrees C, film development is quite rapid, that's a fact. It is also a fact that when ambient temperature and solution's temperature are rather close, it takes a lot of time to change the solution's temperature. For instance, I've developed film at 24C, when the ambient was 30C. The temperature difference from start to end was less than 0,5C. Presoaking and using a water bath will also help in cases like that. You can always test before doing any film development and you'll probably see that it's not hard at all. If you still need to find development times for even higher temperatures, have a look here and specifically at "Converting to Other Temperatures".
 
Here in Turkey I regularly process at 26°C (78.8°F) because that's the ambient water temperature for much of the year, it doesn't ever seem to go higher. Although the room temperature can be a bit higher I find it's remarkable easy to keep the whole process cycle stable and was surprised to find that was within 0.2°C with no water bath.

Most modern films are well hardened but I wouldn't take most B&W films over 30°C, and EFKE(Adox) over about 22°C because their emulsions are barely hardened. But there are specialist high temperature developers which up until digital took over were used for "Photo-finishes" etc for Horse racing, motor sport, athletics etc, these ran at temperatures up to 80°C/175°F with dev times of around a second, using specially hardened thin films, times of 0.2 seconds at 93°C/200°F were achied as well

As you take the developing temperature up with conventional films the risk of reticulation increases, even though the films are well hardened any shock in temperature can cause micro-reticulation also known as grain clumping, visually this just appears as increased grain. So it's even more important to keep the temperature of each step including washing as close as possible preferably within 1°C/2°F.

Ian
 
google is your friend. As is the local library.
the assumption that film is a limiter is partially correct. Physically the film today can handle temps in excess of 80 degrees. Damage to the film base occurs above 100 degrees. I'm not sure at what temp damage to the emulsion occurs.

It isn't the film, it isn't the chemicals. It is the interaction, the synergy of the film and chemicals that we like.

If time is on the x axis, and temp is on the y axis we can move it, adjust it to the left and the right up to a point. When you go to the extreme in either direction to steal a term from the economist you reach the point of diminished returns.

If you want to know the science behind it ask a chemist, or an engineer.

You asked an artist so I will respond as one.

Short development times, those under 4 mins, are hard to get consistent results. Each error is magnified because the short duration.

Longer development times give you more latitude. Oops i forgot to agitate 2 times over 10 minutes is not nearly as bad if you forget to agitate twice over 4 mins. Bam the agitation was just cut in 1/2.

Visually the super short development times lose nuance, subtlety.

I'll let the engineer talk about how it changes grain, highlights and shadows. I'll let the chemist talk about the changes in grain size and structure.

I'm an artist and all i can say is it just doesn't look as good.
 
MolBasser said:
My opologies, as that last post reads pretty poorly.

I'm still interested in the science behind the ideas though.

MolBasser
Click to expand...

Dear MolBasser,

Often when you see advice on APUG (as well as other photo forums I'm sure) it is based on practical working experience rather than precise limits set by the physics and chemistry involved.

In this case you will find that many of the Kodak data sheets advise that times shorter than 5 minutes be avoided due to the possibility of uneven development. In the '80s I used to develop Tri-X with a product called Perfection XR-1 which worked at 30°C but for times much longer than 5 minutes (you sound as though you might be a chemist so visit Unblinkingeye.com for more info). As for the time advice, I know I have personally used times shorter than 5 minutes without issue, but my experience in that area is limited to the continuous agitation afforded by a Jobo processor.

Neal Wydra
 

Excellent. I like this answer and agree with several points out of hand.

Short development times will amplify mistakes as you mention. However, given proper attention, this should be able to be mitigated.

*disclaimer* I'm a molecular biologist and brewing scientist, and most of the processes I am familiar with are biological in nature rather than physical chemistry.

I imagine with a little searching one can find the appropriate formulas/tables to dictate the actual chemistry at different temps and also the temp limits of the media that contain the materials.

Anyway, like I said, some of my earlier responses probably read poorly and I meant no disrespect to those with more experience than I.

MolBasser
 
I asked Kodak technical support about this and just received a reply:

"You may certainly process at higher temperatures and extrapolate with the data provided to get some starting points. Since you should try to have all the solutions at the same temperature, make sure that the developer temperature is something that can be maintained through the process. You will not want to use temperatures higher than 85 or 90F."

Apparently, the critical temperature for Kodak's product is at around 85F....
 
Or the dev times are so short that it's impractical to go higher in temp.

Ian's spot on with his advice here. And remember color films are regularly processed at 100F. It all depends on how much hardening the film has as to where the limit is.
 
The formula posted from the Covington article should work reasonably well.

However with Xtol 1:1, TMY-2, and data from F-4043, better fitting coefficients are:

Celsius: -0.0751
Fahrenheit: -0.0432

I've run a lot of data from Kodak J-109 and other places, and there is some variation in the coefficient across film/developer/dilution combinations.

Lee
 
Thank you everybody. I'm going to try using the formula to extrapolate the data with suggested co-efficient and NOT exceed 85F.
 
High temperature processing can be done with regular black and white materials.

Last summer I developed scores of Fomapan 200 sheets (EI 125), 8x10 format, in trays at 32 C (alias 90 F) with flawless results. Precautions included doing the sheets emulsion side up and one at a time. Agitation in Xtol was constant, gentle, and as random as I could make it.

Was the emulsion severely softened by this treatment? I don't know because nothing touched the emulsion side except liquid. And the protocol was easy to remember and do: develop at 32C for 3 min 20 sec! I think I'll make this my standard process.
 
tkamiya said:
Is there such limitation that above certain temp, things start to break down?
Click to expand...

Each developing agent within a developer formulation has a temperature coefficient. Their combined effect on a film to give the characteristic look of that developer will work within a range of temperatures. If you go outside that range one or more of the developers may cease to be effective or the other one/two may take over the bulk of the work. So it's just not that easy to extrapolate beyond manufacturer suggested temperatures, other than to experiment & see if XTOL is still really giving characteristic XTOL results.


"This ratio varies with different developers but remains practically constant for different emulsions...With a developer containing two developing agents, the temperature coefficient operates only through a limited range of temperature, as each part of the developer in effect retains its own coefficient and the proportion of the developing done by each varies at different temperatures, but with metol-hydroquinone the variation at ordinary working temperatures is negligible."

(wow! run-on sentence)

I believe XTOL is a Phenidone/Ascorbic combination. I routinely process at 79F in the winter with PC-TEA (Phenidone/Ascorbic) and have no technical problems (I am suspecting larger grain issues, but I haven't done side-by-side comparisons), but my developing times are from empirical results.



Quotation from Wall & Jordan 1976, "Photographic Facts & Formulas"
 
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