PDA

View Full Version : A practical test of long outdated film



Jim Noel
10-Jul-2014, 15:26
After following a few strands concerned with development of outdated film over the past few years, I decided the time has come to do a comparative test of the same emulsion batch film and compare results then and now. What really gave me the idea was running across a film pack of Tri-X 320 in the darkroom cabinet which was probably removed from the freezer in 2010 when I set about some other experiments. This pack and its remaining nine (9) brothers had an expiration date of Dec. 1967, and all have the same emulsion batch number.
I must note that these tests were fast and dirty, not scientifically precise, but a comparison of the practical use of the film in 1970, goodness it is hard to believe it is more than 40 years ago, and today. I not only utilized the same film/developer combination, but the identical method of development.
Luckily, my files arenít too well organized, I found my EI and development tests from the time when I bought the film in 1970.The notes indicated the use of HC 110 1+63 from syrup for 10 minutes gave an EI of 125. (I have never gotten an EI for this film faster than 160.)
I loaded the film pack and exposed 8 sheets. Four sheets with an EI of 100, and four with an EI of 25. I decided the best comparison would be to use the same developer and dilution as in the past, although I normally use a pyrocatechin based developer and slower films.
Development was in HC 110 1+63 from syrup, for 12 minutes. The additional time was chosen because I decided that the old film is like me and needs all the help it can get. Upon drying the fb+f for the film exposed at EI 100 is .58. High yes, but easily printed through since it is very even across the sheet. Film base+ fog for the film exposed at EI 25 is .70, almost Ĺ stop more dense.
Next came the addition of sodium benzotriazole to the developer. Rather than use the powder I dissolved 2 tablets of Kodak Anti-fog #1 in 91% isopropyl alcohol and added it to one quart of developer. The quantity was purely a guess since I donít find any published data on use with HC 110.
Obviously this set of negatives was rather thin, so I did another pair for 20 minutes. I examined under the green light at 15 minutes, a 25% increase, and decided to go on. In this pair, the negative exposed at EI 25 is visually similar to the EI 100 developed without the benzotriazole. These negatives are OK for enlargement, but the scale is too short for my purposes.
The negatives developed with the benzotriazole for 12 minutes have a fb+f of .46, a very slight decrease, and the shadows are very thin.
The negatives developed for 20 minutes exhibit a fb+f of .69, a big increase of almost a full stop. This appears to me to be chemical fog induced by the long development time.

My conclusion is that the most practical way to use this film is an EI of 100, developed in HC 110, 1+63, for 12 minutes in a tray with agitation 5 seconds each 30 seconds. Since Tri-X has never produced significant expansion it makes no sense to attempt to use it for my normal printing processes. The same is true, and always has been, for all of the higher rated films. It will be used for those rare images I intend to enlarge.

I frankly was amazed at the results. I expected the fog to be so heavy as to mandate the use of the restrainer. I also expected the fog to be uneven across the film, heavier on the edges and lighter in the middle. These expectations were augmented by the fact that this particular film pack had been out of the freezer for so long. I was elated to be wrong.
I guess my next experiment will be to test a few sheets from one of my remaining boxes of 144 sheets of Super XX. It is about time to use this stuff up while I can. Yes, film used to be sold in boxes of 12 or 144.

Happy photographing!