Air bubbles issue - 120 apron developing tank

[alinCiortea]

I have an apron developing tank for medium format and I get air bubbles on the upper 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.

I have two 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)

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...

Am I missing something? Thank you!

 

[Snapshot]

I recall someone referring to the use of film aprons as being "foolproof." Well, call me a fool then because I found them annoying to use and not any easier than a Paterson reel. I used the clear aprons for twist agitation and turn agitation tanks and obtained identical results.

Rap the tank after each agitation sequence to dislodge any bubbles. A prewash may also help eliminate or reduce air bubbles. Also, make sure your tank is completely filled with solution. I can't help but think the sloshing is generating bubbles at the top of the tank due to insufficient fluids.

Hopefully, this will resolve your problem.

 

[Chazzy]

I had a problem using 120 aprons where the bumps on the apron came into contact with the film and interfered with the circulation of the developer. I tried to roll the film and apron loosely, but I finally decided that it wasn't worth the trouble. Do you think that's what might be happening to you?

 

[Jon Shiu]

Curious if you are using photoflo in your tank as it might be a cause of bubble formation?

Jon

 

[Anscojohn]

Over the years, one of the greatest source of air bubble problems I encountered trying to help darkroom persons was in those tanks and aprons. The only suggestion we ever made, aside from get reel (vbg), get stainless, was to be very vigorous in the figure eight movement on the work surface, using the agitation pattern suggested for its tanks by the Great Yellow Father.

Some of the boffins on this board can tell you whether or not the wetting agent in the developer is part of the problem. I do not know.

John, Mount Vernon, Virginia USA

 

[alinCiortea]

Thanks for all the replies!

Jon, I'm not using either photoflo nor any other kind of wetting agent. Developer only (Fomadon LQN).

John, could you please detail the figure eight movement you mentioned?

later edit: got it... you were referring to Kodak but I still don't know it's suggestions to apron developing.

 

[Jon Shiu]

Hi, just to clarify, I meant if photoflo or lfn has ever been in the tank, because in my experience it is very difficult to ever rid the plastic of contamination.

Jon

 

[alinCiortea]

I got it from someone so I can't really know for sure. I'd be tempted to believe no wetting agent has ever been in the tank though. None of my Romanian film-addicted friends has ever mentioned it.

I'll try to see if the agitation produces foam or not without film in the tank later today.

 

[Whiteymorange]

Just a guess, but it appears to me that you might have been short of liquid in the tank. The bubbles will stay at the top - above the film - if you have enough developer. That, along with a sharp rap on the table occasionally, solved my bubble problem.

 

[alinCiortea]

I gave it another try with the tank totally filled with developer. I also used figure "8" movements and short raps of the tank. So far it seems the method is working... no more air bubbles or uneven development.

Thank your for your suggestions!