Need help; a quick simple question. Uneven development, bubbles.

[Yoricko]

Hello,

Where does uneven development due to bubbles occur the most? At the top? Or at the bottom?

Just want to know, because, out of every few rolls, I will have one with a pretty nasty amount of blotches. Not as bad as it sounds though, negatives still savable by spotting (probably quite troublesome too). Going to experiment later today and see if my minimal agitation development is still viable.

Should one hard knock do the job, or does knocking more than one time help?

I usually start with 8 slow inversions over a minute. Followed by just another 8 mid-course.

I will only change my minimal agitation development if that is my only option.

 

[K-G]

If you are quite sure it is air bubbles and nothing else you may try a 2 - 4 minutes waterbath just before the development. Personaly I knock the tank gently but rapidly 2 - 3 times on my stone floor after each agitation cycle. Also make sure that you have enough developer volume so the film is completely covered and with some margin. When agitating, foam is easily formed on the surface when you put down the tank. The waterbath took care of my bubble problems when I started using it about thirty years ago and it hasn't bothered me since.
Keep developing !

Karl-Gustaf

 

[Yoricko]

How much do I need to compensate for if I do pre-soak the film?

 

[Sirius Glass]

Get a linoleum block cutting pad from an art shop. Every time that you fill the tank, thump the tank on the pad several times quickly. After each inversion adjitation thump the tank once. This cured all my air bubble problems.

Steve

 

[Gerald C Koch]

Eight slow inversions over the first minute is not correct. Kodak recommends constant agitation during the first 30 seconds. Then two to three inversions every minute. The inversions are not just a simple inversion but also contain a swirl. Look on Kodak's website for a diagram. Also as mentioned you should rap the tank a comple of times each time it is filled. Be careful not to overfill a tank as this prevents circulation. For a Nikor style tank (single roll) this would be 240 ml. Some people presoak but this is a matter of personal taste rather then dogma. I personally do no do it and have never had any problem.

 

[Rick A]

If air bells are a problem, then add one drop of Edwal LFN per batch of developer, no more bubbles. Pre soak for two or three minutes does help, but a little insurance with LFN cant hurt.

 

[K-G]

How much do I need to compensate for if I do pre-soak the film?

Compared to your normal development time , aproximately 10% according to what I have read in other sources. Normally I use the standard times from the film and developer fact sheets and that has worked fine. I think you have to do your own testing.

Karl-Gustaf