air inclusions during developing

[alinciortea]

I have a corex band developing tank (I'm not really sure this is how they call

it) for medium format and I get air bubbles on the lower side, 1 cm wide, for

the entire length of the film. I've agitated it quite hard with

clockwise-counterclockwise moves for about 15 seconds before closing the tank

and another 15 seconds afterwards, yet the bubbles are still there, although I'd

hoped all air inclusions would rise to the surface of the developer after all

that agitation.

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Am I missing something?

Thank you!<div></div>

[Vlad Soare]

I believe it's called a film apron. :-)<br>

But I've never used one, so I can't help you.

[alinciortea]

that's right :)

 

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i have two such aprons, one made from clear plastic and one from white opaque plastic. both seem to have similar dents. how can i distinguish between agitation aprons and turning aprons? (my tank - TRIPLEX - is an agitation tank)

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i used the white apron for my first two rolls developed in this tank. it has a plastic clip used to fix the rolled apron to the reel. both films got stuck to the apron on the lower side for most of their length. someone told me it was due to the clip that was keeping the apron from freely move inside the tank during developing so i'd tried the clear plastic apron that lacks the clip. indeed, no more film sticking to it but instead the air inclusions appeared. i'm really confused...<div></div>

[franklin_h1]

I'm not familiar with that tank but in general to help dispurse air bubbles give the tank bottom a couple of good raps on your work surface.

You might try adding developer in the tank first then slipping the film reel in next.

And make sure you have enough dev in the tank to completely cover the reel.

[franklin_polk]

My thoughts were the same as Franklin H's, it looks like you didn't have enough developer to fully cover the film, which allowed the 'suds' to cling to the areas of the film that were not immersed in developer.

[alinciortea]

initially i thought the bubbles appeared on the side to the bottom of the tank, but indeed, after some calculations, the upper side was affected. yet, at each agitation i have a very small quantity of developer spilling out of the tank and i thought this means thereţs more than enough developer inside...

[ronald_moravec1]

No matter how you cut it, there is not enough developer touching the film. Perhaps the apron is moving up and not coming down. Someone wrote about the very same problem with the same picture. His reel was not staying on the bottom.

 

Your film and apron is moving up and the top of the film is out of developer when in the dark.

 

Do what the others said also. Also do not use photoflow or wetting agent in the tank as residual agent can cause developer to bubble.

Scrub with bleach if you have done this already. Then let it soak 24 hoursw, scrub again.

[blarg_.]

tapping the tank on a hard surface after every agitation should dislodge bubbles...however, make sure that it is, in fact, air bubbles and not something else like bad reels, or some funky reaction releasing gas during development.

 

If worst comes to worse, pick up another tank on ebay - you can usually find a cheap, slightly used one being sold by photo students on ebay. I got a Patterson tank that looked like it had never been used for $15 shipped. The tank is fantastic and I highly recommend it. It uses about 15% more fluid, but it's totally worth it. Easy loading, and I haven't a single frame of ruined film since I switched from steel tanks/reels.

[fourthst]

Alin, Ronald, Edwal makes a low foaming non ionic (I think that is how they bill it) wetting

agent, LFN, that I have used in the developer with good results. It is non reactive so it doesn't

change developer characteristics and does not cause too much foaming if any. You could

also try a pre-soak in Edwal's, or other non reactive, wetting agent bath.

[fourthst]

Alin, I didn't see the first image. As the others have said, you are not getting developer to

that section of film and it could be that the apron and film are floating in the tank. Perhaps a

spacer of some sort at the top of the tank that would keep the apron submerged would work.

[alinciortea]

thank you for your replies! i'll try to work something our for the next developing, compiling all the info received. :)

[david_dorcich1]

Kodak made a tank that uses rolls similar to what you have shown. It had a metal disk that was perforated to let chemicals flow that went over the roll to keep it from floating. Is there something similar for your tank?

 

I have one laying around with all the parts, i'll check when i get home.

[blarg_.]

I just remembered seeing those aprons in my photo class...and being warned to NEVER use them because they're a pain in the butt.

[alinciortea]

my tank has no disk but the vertical movement of the reel it permits with the cap closed is of about 1cm.

 

i've also heard many complaining about aprons but i guess it's a matter of getting used to one system or another as each comes with its advantages and disadvantages.

[Monophoto]

Insufficient developer. The fact that developer leaks out of the tank when you agitate indicates only that the tank leaks, not that you have enough developer.

 

Suggest loading the apron onto the reel, placing it in the tank, and then filling the tank with plain water (without the lid) until the reel and apron are fully covered. Transfer the water to a graduate to determine how much is required to cover the reel and apron. That would then become the amount of developer you should use.

[alinciortea]

I had another try with the tank totally filled with developer, associated with figure "8" movement and short raps of the tank. It seems this process works fine.