A truly unique question about HP5 and TRI-X

[rita_rathbone]

I teach photography in a high school on a 55 minute class schedule.

Sometimes we have interruptions (fire drills, bomb threats, drug

dogs...)or weather delays and students can't finish developing a

roll of film. In the past, I have let students finish whatever step

they are on and leave the developing tank filled with water and

finish the film the next day. I know this is not excellent

technique, but it worked just fine in a pinch. The times I have done

this before, it was using Tri-X, but I have learned the hard way

that it does not work with HP5! The emulsion seems to just soak off

and leave perfectly clear film base! The chemicals were the same

for each type of film. What is the difference between the two films

to cause this? Could this be related to the fixer having hardner or

not? Any advice on what to do if the processing MUST be interrupted?

[peter_dendrinos1]

Sounds like you need a student aid. Someone who can come in and finish things up and clean up the darkroom. Or perhaps a photo student with a study hall during the next class.

[rowland_mowrey]

Rita;

 

This could be one of 3 things.

 

1. The hardener used in the film itself.

 

2. The subbing layer underneath the emulsion layer.

 

3. The means used to 'attach' the subbing/emulsion layer to the film surface. The film surface repels water, and the emulsion and gelatin is coated from water, so there has to be an intermediate treatment method that permits attachment that overcomes this hydrophyllic-hydrophobic barrier.

 

If any or all of these fail, you get the emulsion coming off of the film support.

 

If it is #1, you see virtually no residue, just a dark gummy mess in the water you use to soak the film in. If it is #2 or #3, you can see 'sheets' or 'curls' of emulsion that 'peel' off the support rather intact. Of course, it can be a mixture of all 3, etc.

 

I know that TX is very hard and can withstand some pretty rough treatment. I don't know about the HP5.

 

If it is coming off the support in the wash after the developer, then there is not much you can do unless you hold it in an acid hardening bath instead. I suggest you use the hardener portion of a hardener fix. You can buy individual bottles of hardener from mail order or local photo supply places. It is not a good idea to hold any film at a basic pH for extended periods in any case. The gelatin can degrade even with the best hardening.

 

Regards.

 

Ron Mowrey

[ronald_moravec1]

Why not try some experiments on your own. I would maybe try leaving a little water in the bottom so the film is not touching it and caping the tank to retard evaporation. Wet is probably not as bad as imersed.

 

Rewet totally before continuing. If you stop in the developing step, just forget it.

 

How about a few student aids who have study hall next hour to help finsh. A person could do 2-3 tanks at a time.

 

A few deep tanks might be able to take all the partially completed rolls a one time. Have all the students start at the same time so there is some consistency to how much more need to be done.

[richard_cochran]

I'd suggest avoiding the problem in the first place. Keep some

fresh rapid fixer on hand. If you need to do "expedited processing",

finish developing, and throw the film directly from the developer

into rapid fixer for two minutes, rinse, and hang to dry. The next

day, fix and wash more thoroughly for permanence.

<p>

Super-long wet times cause the emulsion to swell and distort under

the best of circumstances. Even though it was more-or-less working

for you with Tri-X, I'll bet details will look better if you don't

allow the film to stay wet so long.

[tgh]

Rita,

 

No one has mentioned it, but bravo to you for teaching traditional BW photography to HS students!

 

I'm thinking along the same lines as Richard - you might need to change the choice of chemicals you use slightly, but it's been my experience that using HC110, Stop-Bath, Kodafix, hypo-clearing agent to cut the wash time & Photo-Flo to aide drying it's possible to get a fully developed roll of either Tri-X or HP5+ done and hanging out to dry within 35 or 40 minutes. May be some loss of absolute negative quality, but that's moot if you don't have the luxury of time.

[david_goldfarb]

The best answer is obviously to find some way of finishing the processing, but lacking that, I wonder what would happen if you were to leave the film in a sodium sulfite solution after the stop instead of in plain water. The reason it occurs to me, is that Polaroid type 55 is cleared in an 18% sulfite solution instead of plain water in part to prevent emulsion swelling, and Polaroid says the film (which is Panatomic-X) can stay in the solution for 72 hours. The only downside would be that it might weaken the fixer, so it would probably be a good idea to give the film a rinse after the sulfite holding bath. I suppose that if you were to use it between the developer and the stop it might also have an undesired solvent effect, so since the stop bath is a relatively quick procedure, it's probably best to use it only between the stop and fixer.

[jay ott]

I think a time saver would be to have the students come to class with their tanks already loaded with their film. 55 minutes goes by pretty fast when you have to load a stubborn roll or reel.

[lex_jenkins]

This may be among the reasons why Ilford specifically recommends against presoaking their films.

 

This is one of the rare cases where I'd recommend using a fast acting developer, such as HC-110 at Dilution B. This cuts development time from 10 minutes or so with many developers (including more dilute HC-110) to only 5-7 minutes with Tri-X. I used it this way routinely as a photojournalist and got good results, even when my measurements were sloppy.

 

Don't bother with a stop bath. Plain water is good enough for film.

 

Use liquid concentrate fixer at the more concentrated 1:4 solution. This enables fixing within two minutes in fresh fixer.

 

The Ilford archival method for washing film on the reels in the tanks takes only a couple of minutes. I forget Ilford's exact recommendations but I use 10 inversions for the first tankful, dump and refill with fresh water, another 20 inversions, dump and refill, another 30 seconds.

 

If you have time use Photo-Flo or other wetting agent at the end to minimize spotting.

 

With a good workflow, having materials prepared in advance, and a bit of luck, it should take 10-15 minutes per tank of film.

 

In the interest of having materials prepared in advance, I'd premix enough Dilution B to last the entire class for a week. This ensures more consistent mixing and saves the time it takes fiddling with litle measuring devices to mix fresh from the syrupy concentrate.

 

As a last resort I'd experiment with rinsing the film in clean water at whatever stage in the process it's in, agitate a few times, dump, and let the tank sit empty of liquid 'til the next class.

 

As a last-last resort there are single bath methods for developing and fixing film. The theory is that as the film development finishes the developer becomes exhausted by the fixer, which finishes up the film. I've tried, unsuccessfully, to homebrew such stuff. And it won't really teach your students good darkroom technique.

[patrick_ingram]

Drug dogs? Your school isn't, perchance, in an airport? I had a

fire alarm go off a while ago in the middle of my developing cycle

(I use a darkroom in a university). I dumped out my rodinal, rinsed

once with water, and then filled the tank with clean water. When

the crisis was over (a false alarm, but a few months earlier there

was a small fire in that building, so I didn't want to take a

chance) I mixed up some fresh rodinal and picked up where I left

off. The film was HP5+, and it was fine.

[oskar_ojala]

<i>This may be among the reasons why Ilford specifically recommends against presoaking their films.</i>

 

<p>I don't see a connection; typical prewash times are 30 sec. to 1 min. and if the film can't stand that, how can it stand going through the development process?

 

<p>The advice of trying to shorten processing times, using faster developers etc. is good. With a stop bath, something like 20 sec. with agitation should be enough (Ron Mowrey can fill in the details if I remember wrong...)

 

<p>Try also to think how you can speed up the entire process - what can be premixed, what can be ready when the students come etc.

[rita_rathbone]

Ok,some of you obviously have not spent any time in a US public high school recently! There is no such thing as study hall anymore and yes, bomb threats and random searches using the drug dogs are routine. Anyway, we do not do this regularly, it is considered a last resort. I just thought is was an interesting question...

 

There was a suggestion of hardner, should this be used straight or diluted? What dilution? Some of you are suggesting letting the film dry in the tank or the dryer without a good washing. Wouldn't that lead to chemical fog?

 

Thanks for all the responses...keep 'em comin....

[kirk_keyes]

Hardener is not your answer - it is used in the fixer, so if you have to pause processing during the middle of developement, hlow is that going to help. Definitely look at shortening steps as suggested above. Also, you may be able to save time by raising porcessing temps of that the steps can be performed faster.

 

Perhaps not using HP-5 is your answer - go back to Tri-X.

[richard_cochran]

<cite>Some of you are suggesting letting the film dry in the tank or the dryer without a good washing. Wouldn't that lead to chemical fog?</cite>

<p>

Eventually, perhaps. But chemical fog won't develop overnight. I suggested doing a shortened fix followed by a quick rinse and drying. Then, the next day, you can do the full fix and thorough wash, perhaps with hypo clear, for permanence.

<p>

Then again, if you only need the negatives to last until the end of the semester, maybe you don't need to do that much. I used to work in a newspaper darkroom on a deadline, and when under pressure, we

would often open up the tank after a few seconds of fixing, and

look at the film, fixing by inspection only until the film just

barely cleared. Then we'd wash for 10 seconds or so and take

the wet negatives to the enlarger to print. We never bothered

to go back and re-fix or re-wash the negatives. Sometimes

I had to reprint the negatives after a few weeks, and they

definitely were OK for that long. We had some ugly discolored

brown negatives in our files that were a few years old -- this

technique was most definitely NOT archival.

<p>

But more than once, it got photos to press before deadline,

when a lot of people would have been screaming at us

if we had taken time to do the thorough fixing and

washing cycle.

[phillip_p._dimor]

Perhaps you could have an emergency kit? A gallon of water, stop bath, rapid fixer and an empty bucket for used developer? Throw in a timer, funnel and changing bag and you could have students finish things outside or in a bathroom possibly? You could keep most of the small goods in the empty bucket and have other students carry the water, stop and fixer.

 

Not sure how your school works. My school (before public schools turned into mini-prisons) used to have students congregate outside where the teachers and police would oversee the students.

 

Just a thought, sorry if this doesn't really answer your question about emulsion separating from the film base..