bvy
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I am unaware of any real scientific investigation that determined that temperatures in the range listed have any advantage in the recovery of images from old film. If someone knows of such work please specify the links. Otherwise the link given is pure speculation.
Just now catching up. Why should I be lucky if anything at all shows up? The film stayed in the camera and wasn't exposed to the elements...You have just one roll and you are going to use a process and temperature you have never used before? Just process it as you would any other roll. You will be lucky if it shows anything.
Anyway, the one thing I AM sure of is that HC-110 does NOT become inactive at 40F as some have claimed. At least not for me anyway, and at least not in the sense of its activity completely falling off a cliff at that temperature. You definitely can develop at those temperatures.
Here is a sample from a roll of Verichrome Pan found in an Imperial Reflex 620. Based on my clip test with HC-110(A) at 40F, I chose 9min 15sec for the development. Interestingly enough, if you compensate for dilution and temperature you actually come up with pretty much the same development Kodak gave for this combination originally - 6min at 65F with dilution B.
Bvy, did you ever get this roll developed? I am very curious to see how it comes out.
In the meantime, I think I found the online reference that first turned me onto the idea of developing at colder temperatures: http://silverbased.org/dev-old-vp/. Apparently the author of the site ("Vox") got the idea from information in C.E.K. Mees 1942 text, The Theory of the Photographic Process. He writes, "But I discovered one intriguing table on pg. 455. This listed the ratio of image density to fog density, for various developing agents used at different temperatures. What leapt off the page was that for certain developers, the image-to-fog ratio was twice as good at 15° C as at 25° C." Researching this further, it turns out that there is an online text of The Theory of the Photographic Process available free of charge! If anyone would care to have a look at this and digest it, I would be interested to hear whether you agree with Vox's conclusion. HC-110 is supposed to be a phenidone-hydroquinone developer if that helps.
Jeff
I tried to look at two tables on development time compensation,( Ralph Lambrecht's and Ilford) and neither go any near as low as 40F but the Ilford one does go to 56F and the difference is about double the development time but your compensation for HC110 is not much more than 50%.
As Ilford doesn't bother with temperatures below 56F I'd assume rightly or maybe wrongly that Ilford's developers do not work well, if at all, at 40F.
Clearly there is something different about HC110 in terms of time adjustment for lower temperatures and maybe something different that enables it to work at these incredibly low temperatures.
I wonder what this "something different" is?
pentaxuser
Well if I read that correctly, it looks like what you want is p-Aminophenol, not HC-110!
Duncan
I would like to point out a few things.
The information cited in Mees mentions a temperature of 59F when converted. It says nothing of developing at 40F. At the time it was known that different developing agents produce different amounts of fog.
The information is based on emulsions in existence before 1940. It also cannot refer to HC-110 which hadn't yet been invented. One cannot assume that the information would still apply to emulsions from the 1950's or later. There are have been warnings on APUG about relying on the technical data in old photobooks. In the case of Mees the data is more than 75 years old!
Sorry but the premise mentioned in the article cited in the OP remains conjecture. There still remains no scientific evidence that development at low temperatures produces any better results than normal development. One would have to cut a roll in half and develop each at different temperatures. Then use a densitometer to measure the fog levels.
BTW, the rule is that the rate of any chemical reaction doubles for each 10C increase in temperature or halves for a 10C decrease.
DD, did you see the link in my OP? The blogger/photographer there shows results with HC-110 at 44F.
http://foundfilm.livejournal.com/12334.html
So,bvy, what did you decide to do in terms of time and developer and what happened when you came to develop the film in the months that have ensued since your last post on the subject?
Thanks
pentaxuser
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