Help: Origin of "fish scale" marks on film

[jmw__]

I just started shooting and processing my own 4x5 B&W film. I'm shooting with TMAX

400, loading, unloading, and processing the film myself. I'm using a Jobo 2551

multitank and using the hand roller.

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I spent a couple of weeks shooting and processing film. Looking at the shots, I saw a

bunch of "fish scale"-type marks on the several of the sheets:

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<img src="http://www.photo.net/photodb/image-

display?photo_id=1759051&size=lg">

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It looks a bit like reticulation, but and here's the strange thing the

marks only seem to occur in the corners.

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I suspect that this might be a problem with the lens, but can't be sure. Has anyone

else seen this sort of thing? Could it be something other than the lens?

[carl smith]

Disclaimer: I really honestly don't have the experience in this and I don't know that processor real well but...

 

It looks like bubbles of some liquid dried on the film.

[jmw__]

Carl:

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Dried bubbles are exactly what this looks like. But would one lens accentuate the

effect more than another lens? And the marks are not appearing anywhere near the

center. In all other respects, the image is very sharp.

[jorge_oliveira2]

I've always heard that lens dirt or fungus would not show up on prints - just cause a contrast loss.

 

But, with this misterious thing (the marks are only at the corners), I would try each lens shooting a flat wall or whatever at middle scale (Zone V).

[lex_jenkins]

Bubbles. Foam. That's what it looks like to me. Do you use any wetting agent in the tank? Any residue can lead to foaming the next time you process. Ditto if you wash your tank using any kind of soap, detergent, whatever, and don't rinse it thoroughly.

 

Doesn't take much wetting agent, soap, whatever, to produce foaming. Many developers are alkaline - that'll boost the foaming. Again, I've tested this, it happens.

 

Heck, some developers will foam up pretty good even in the absence of any additional wetting agent if you agitate enough. Take something like Rodinal - save your next batch after use just for this test; add a pinch of borax; shake it up. Presto - bubbly. My print developer, to which I've added a pinch of borax, foams up like a pint of Boddington.

 

You might try soaking and re-drying the film. Might help. Or crop around it and tighten up on those darkroom practices.

[carl smith]

Well, depending on the type of shot it will be more obvious on the film. And the corners that were hanging down when it was drying might accumulate more foam (logically) than the center and would take longer to dry.

 

I bet its the same on most of the shots, but the type of image detail or order of developing might change it. I always hand deve 4x5 B&W with dip and dunk and am meticulous about avoiding foam when finishing up.

[greg_smith4]

This happened to me once. Looks like foamy Foto Flow that dried.

[jmw__]

I borrowed a better loupe and took a close look at all of my negatives, and it turns

out that on closer inspection, the bubbles showed up on photos taken with my other

lens. So at least it's not the glass!

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I tried soaking and re-washing the film-- the bubbles were still there, so it's in the

emulsion.

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I'm going to mess with my controls a little bit and try shooting some film from other

batches. I recall that the Jobo reels were a bit slippery with a viscous lotion-like

substance new out of the box (those of you who use Jobo reels will know what I'm

talking about). I washed them very thoroughly until they were tack-clean, but perhaps

there is some residue left over? Very frustrating.

[jmw__]

I used different search strings on photo.net and found reference to the 2509 reels

that I'm using.

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I read that the older series were conducive to the bubble problem that I'm having. I'm

using the newer 2509n reels.

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Hoping someone can help me answer some questions:

<ul>

<li>I'm hand rolling, 30 seconds at a time in each direction. Should I also be rapping

the tank as well? (I was under the impression that since there was constant agitation,

the tank-rap wasn't necessary.)

<li>JOBO says that I can develop up to 6 sheets at a time in on reel. Is this to be

trusted? Should I be developing on 2 or 4 sheets at a time?

</ul>

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Thanks to everyone on this forum. Your answers have been very helpful.

[ann_clancy3]

We have had this happen recently in our lab and think it is the result of photo flow. Someone didnot clean the reels properly and then the next person came along using the same reels, or perhaps the tank and ended up with the same problem. I did lots of research about this, as this is the first time I have ever seen anything like this (50 years of darkroom work) Altho, the marks are found everywhere they are most clear in sky's, must be all that zone V shade. The most common answer I got back was a "foaming action" created by residue wetting agent.

[jmw__]

I don't use Photo-Flo, and since I've re-wet and dried the film without any change, I'm

ruling out that any problems related to washing and drying.

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I'm thinking that either I'm not rapping the tank enough, or perhaps there was some

residue left over after I washed the tank and reel (which I do very thoroughly with hot

water and diluted soap). But I'm also worried that either a) the film is too close

together on the 2509n reel, or b) I'm not rapping the tank enough (which is strange,

because I thought with constant agitation you didn't have to rap the tank to dislodge

bubbles...

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Perplexed.

[lex_jenkins]

I'm gonna take a wild stab here and suggest using a dilute mixture of either distilled white vinegar and water or stop bath and water - warm water - to rinse out the tanks and everything that comes into contact with the film.

 

Then feel the wet surfaces to see if they're "squeaky" clean. If not, up the strength of vinegar:water. This is what I use to clean my stuff. The amount I need varies throughout the month according to how much salt is in the softening filter for our rural well water.

 

Just don't use any kind of soap, unless it's specifically designed for darkroom use (if there is such a product). Otherwise you may be back in the same boat next time.

[carl smith]

Photo Flo works fine but you need to wipe off the excess with a squeegee or the side of your hand. I never just pull it out of the tank and hang it up to dry. The same goes for 35mm, where I'll pull the whole stip of negs through two fingers to pull off the excess photo-flo.

 

You only need a dab of photo-flo if you're going to use it. I've never followed any instructions for it. But I'd say I trow in maybe 5 or 6 drops worth for a regular deep tank but it's been a while.

[ann_clancy3]

The problem with photo flow occurs when the reels and tanks are not cleaned properly after use. THey dry and then there is dried chemical residue which bubbles when new liquid is placed in contact.

 

As an aside, with Kodak's version we use about 1 drop to a liter of water. Wipe with fingers only. With my personal work i use Edwal's with distilled water and just hang. No water marks. We tested various ratios, water and techniques before arriving at a final method.

The fish skin effect is not from water streaking they look more like items found under a miscrope.

[richard_urmonas]

With the Jobo reels you can only do 4 sheets per reel. They originally

said 6 sheets, but there were problems (I think it was some films

flexed too much and touched) so they ammended it to 4 sheets. Leave

the middle slot empty.

 

Secondly check the tank is completely level when on the roller.

There is very little fluid in the tank, and a slight incline

could be enough to stop the developer etc. reaching the film at

one end.

 

Finally 30 seconds in one direction sounds a bit long. The machine

only gives two revolutions in each direction at 75 rpm. Before

I had the machine, I would roll the tank up and down the edge of the

bench. Only 2-3 seconds in each direction. Results were good.

[jmw__]

Richard:

 

Thanks for the very helpful feedback. Changing rotation direction every 2-3 rotations

seems like there would be lots of developer sloshing about and causing bubbles, but I

will definitely give it a try.

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Do you know of a source (printed or on the Web) that recommends 4 sheets in

2509n? Their Web site still says:

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<em>2509N 4x5" Sheet Film Reel Holds up to 6 sheets of 4x5" film</em>

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When you process 4 sheets, is the black retainer still necessary?

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John

[chris_waller]

Yes, they're foam marks. These can be avoided by (i) ensuring that the tank is thoroughly washed out after use to remove any wetting-agent and (ii) not over-agitating. After washing film I dunk the reel in a jug of water plus wetting agent to avoid getting any wetting agent in the dev tank. I use the Ilford hand-washing method which washes the tank out at the same time so it seems illogical to re-contaminate the tank by putting wetting-agent in it afterwards.

[chris_waller]

I meant to add that these have occurred during development so nothing will shift them. I once had exactly this same problem which ruined the shots from a portrait session.