Spot marks on film

ericdan · Aug 23, 2016

Could these be marks caused by bubbles in the developer?
I have been using the same method for a while and not seen any issues like this.
Neopan 400, D-76, Paterson tank

I noticed the same marks on another roll of Neopan I recently developed.
Haven't seen this on other films before.

goros · Aug 23, 2016

Something like this? These were the result of bubbles stuck to the film while developing, due to a bad agitation method.

bence8810 · Aug 23, 2016

Strange that you haven't seen these before and now suddenly. I assume you didn't change anything in your developing method.

For bubbles, what I do is I slam the tank to the kitchen sink after every agitation cycle. I normally put a small towel on the sink so the neighbors won't call the cops on me. I do slam it quite firmly.

Ben

ericdan · Aug 23, 2016

I think I need to slam it harder after each cycle.
I haven't changed anything in my development method. I'm surprised to see bubble marks all of a sudden.

MattKing · Aug 23, 2016

What type of water do you use for your developer?

ericdan · Aug 23, 2016

tap water until now. After seeing these marks I ordered 6 liters of distilled water.
Don't wanna take any chances again

LAG · Aug 24, 2016

ericdan said:
Could these be marks caused by bubbles in the developer?

Excuse me Ericdan

Rather than bubbles, are much more similar to small bells (without transparencies inside the circle), caused by air either way. A poor developer mixing does not help indeed, and bubbles & bells also appear due to changes in temperature ... Anyway, it is not only agitation but rather the standing time.

Looking to the attached files, I also appreciate other details: scratches and an excessive agitation

ericdan · Aug 24, 2016

The Paterson tanks are plastic and pretty good at keeping temperature steady. I started at 19.5 degrees Celsius.
Agitation method used was 10 sec every min (+60sec initially)
I can't check for scratches until after development. Not sure what to say here.

I think a pre-soak would help with bringing the film up to temp before I pour in the developer.

Hatchetman · Aug 24, 2016

They do look like air bells. Give the tank a real good whack immediately after pouring in the developer. But hold on to the bottom of the tank so you don't knock the top totally off the tank. Did that once.

foc · Aug 26, 2016

I have been developing B&W film professionally for the last 35 or more years and I never had this problem and I never had to slam the dev tank. I have never used a pre wash and I gently pour dev into the tank from a 1 Lt graduated cylinder, then a swirl agitation for 10 sec and then every minute.

Just saying.

Terry Christian · Aug 26, 2016

You didn't mention how much developer you're using. To help guard against air bells, make sure you're using plenty of solution, enough to completely cover the film. (Add about 10 or 20 mL, at least, to the prescribed amount on the bottom of the Paterson tank.) If developing only one reel in a two-reel tank, put an empty reel on top to keep the film reel submerged.

Dali · Aug 26, 2016

I would understand the air bubbles reason if it were stand development. But as the OP agitated the tank every minutes, no real reason to still have bubbles.

Spot marks on film

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