Same tank, two rolls, different results.

[paul_sauer]

Hi,

 

I loaded up a Patterson tank with a reel of FP4 on the bottom spindle. I left this roll in

the tank undeveloped for a month, exposing it to air. Then I put in another roll of

FP4 and developed both rolls in the same tank 8 hours later.

 

The newer roll came out perfectly. The roll that had been in the tank for a month was

drastically lighter, as if the images wanted to slide off the film.

 

Both rolls were shot with the same camera, a Nikon F100.

 

Does leaving a roll on a spool in a light-tight tank for several weeks degrade the

latent image?

 

Thanks in advance for your thoughts.

[maury_cohen]

Are you sure the first roll wasn't a faster film? Check the edge markings. Are they lighter as well?

[Fotohuis RoVo]

>> Does leaving a roll on a spool in a light-tight tank for several weeks degrade the latent image? <<

 

Yes in a long time it does. The base fog will go up, so you will loose quality. But this will happens over a much longer time over a year, for low speed B&W over more years and also depending on the temperature.

 

In a month time this is not the cause of your failure. Are you sure the same films are in and exposed on the same iso rate?

 

Best regards,

 

Robert

[markrinella]

Sounds like a light leak in the tank. I am not sure how light tight "light tight" really is. Even

a miniscule exposure would be cumulative over a month.

[maury_cohen]

That would make the negatives darker Mark.

[rustys pics]

It seems odd...there should not be that big a difference. I just developed a roll of J&C Classic Pan 200 that had been in the tank for a couple of months...no big changes.

 

How do you agitate your tank? Is it over and under, figure 8, or slosh?

That could make a big difference.

[maury_cohen]

I wonder if there could be some kind of chemical vapor in the air while the film was sitting that might inhibit development?

Or is it possible the roll sitting in the tank was also much older film?

[lex_jenkins]

With pushed (underexposed) film the latent image will definitely degrade fairly rapidly. In my experience shooting TMY at 1600 there was nothing below the low midtones after waiting a month before processing.

 

Most normally exposed films shouldn't suffer degradation of the latent image that rapidly tho'. Look around the area where you stored the tank. Are there any sources of materials that might become airborne as mists, vapors, gasses, etc., and affect the film?

[roger krueger]

Like Lex, I've seen pretty notable image loss in pushed films left sitting. It's more

noticeable with pushing because you don't have any "spare" shadow speed that'll hide the

speed loss. On normally-developed film it's seldom noticeable.

 

How about the density of unexposed areas? Does it match between rolls?

 

If it's thicker on the "old" roll, that suggests a light leak. In the (extremely unlikely) case

you've got any mercury products like intensifier or old batteries sharing the storage area

that would cause of fogging too. Also, with plastic tanks there doesn't necessarily need to

be an explicit leak--most black plastic is at leaast slightly transparent to infrared. While I'd

assumed that "normal" films had absolutely zero IR sensitivity, I did fog a roll of Tech Pan

(which has some very-near-IR sensitivity) by leaving it in a plastic tank in room light for a

couple of days. I'm sure it was the IR because the exact seem treatment of a roll of TMY

yielded no fogging.

 

If the base density is the same, that makes me think latent image degradation, like Lex

said. Could also be a shooting problem, something like exposure compensation left on,

DX film speed picked up wrong, whatever.

 

If it's lighter, that means it got less development, or got otherwise hosed in a way that

affected unexposed as well as exposed film.

 

Where was this stored? It seems unlikely but could enough fixer vapor get into a tank to

cause trouble with extended storage? Do you wash your film in the tank also, and do you

put the lid on for washing? There could have been fixer left on the tank or lid if they

weren't part of the wash process.

[ronald_moravec1]

Film left in brass Leica cassetts will loose speed the same way according to my mentor woho was a prolific wedding photographer in the 50`s-70`s.

 

I think it might be fumes from plastic outgassing. Brass smells funny too.

[paul_sauer]

Thanks everyone for your best educated guesses. I have been banging my head

against my enlarger trying to figure out why these two rolls -- both properly indexed

for ISO in the camera -- came out so differently.

 

I think I've figured it out.

 

The problem roll was at some point x-rayed while I was travelling. I can't remember

if I made the mistake of putting it in my luggage or if my camera bag was x-rayed as

I went through the security checkpoint.

 

This is now my leading theory. What do you think?

 

Thanks again for your help.

[peter_svensson]

Paul, for clarity, did the first film come out denser or thinner?

[paul_sauer]

It came out much thinner.

[ronald_moravec1]

X ray would make it dark. If the leader is ok and frame numbers ate ok, it was exposed wrong or I will stick with my outgassing theory.

 

You can always recreate the situation with a sample roll to see if it repeats.

[rowland_mowrey]

This is off the wall, but think about it please.

 

Those of you that have used Ilford paper may have noticed the strong odor it has when freshly removed from the package. This odor is a phenolic odor from one of the paper's constituent chemicals.

 

Many films and papers contain volatile chemicals and are sensitive to volatile chemicals. One common chemical is formaldehyde. It is present in new clothing as a sizing agent, and in new furniture as an ingredient in glue. Exposure to formaldehyde will slow B&W film down due to excess hardening, and raise fog due to it being a reducing (fogging) agent. In color film it destroys couplers, particularly the magenta.

 

Outgassing (evaporation) of volatile chemicals from film can also change the sensitivity. I would guess that loss of that phenolic chemical from Ilford paper would cause it to change a bit.

 

The space program was concerned about the loss of volatile chemicals during exposure to the vacuum of space and the moon. This turned out to be a non-problem. On our usual orbital or moon trips, there was no observed film problem related to vacuum induced outgassing from films.

 

Here in our atmosphere though, the presence of pollutants and moisture can be important, and who is to say that a recent chemical addition to film may not have changed the observation in the above paragraph.

 

Therefore, it is possible that the unrolled film in the tank was able to lose volatiles and absorb volatiles both. I don't know which one took place, but that might be the only explanation that fits what you observe.

 

Ron Mowrey

[patrick_gainer]

According to Paul, "The newer roll came out perfectly. The roll that had been in the tank for a month was drastically lighter, as if the images wanted to slide off the film."

 

The clue may be in the edge and between-frame areas. If they are the same density as the good roll's, the problem has to be either underexposure or some kind of loss of latent image. I have developed film that was older than that with no apparent loss of latent image. I haven't looked up vapors that might cause that kind of loss. Most of the ones we are warned about cause fogging, which would increase the base + fog density and cause greater image density but less contrast.

[__hank_boneroneo1]

<exposing it to air.>

 

What kind? Like right next to the cat litter box?

[johndc]

"Those of you that have used Ilford paper may have noticed the strong odor it has when freshly removed from the package."

 

I assume you're referring to that awesome "new film" smell?

 

Best Smell Ever.