spots on 120 film only

jacnorectangle · Mar 2, 2016

I keep getting these spots on my Portra 120 negatives usually in the sky or scenes that have big white areas. But some sky shots on the same roll are clear. They're definitely there in the negative, it's not something I can scrape off. It never happens with 35mm Portra though. I develop them in a Paterson tank big enough for 1 reel of 120 using Kodak LORR developer, a homemade stop bath with 1 part white vinegar 4 parts water, the kodak bleach, fixer, and final rinse. Continuous inversion for first 25 sec, then 2 inversions every 15 seconds. With the stop bath I do continuous inversion for 30 seconds then a 3 minute rinse under the faucet.

RobC · Mar 2, 2016

they look like drying marks but...

what %age dilution is your stop? If stop is too strong it can cause gas bubbles in emulsion. You can often hear this when paper processing. The print starts squeaking when you put it in the stop bath as the gas escapes.

jacnorectangle · Mar 2, 2016

RobC said:
they look like drying marks but...

what %age dilution is your stop? If stop is too strong it can cause gas bubbles in emulsion. You can often hear this when paper processing. The print starts squeaking when you put it in the stop bath as the gas escapes.

If it were drying marks wouldn't I be able to wipe them off? They're inherently in the picture as if I had photographed UFOs. It's 25% vinegar. I'm thinking it has something to do with there being more room in the tank when developing 1 reel of 120 as opposed to 2 reels of 35mm which fills up the whole tank.

Sirius Glass · Mar 2, 2016

Did you use stabilizer after the last wash? It should be the last chemical used. IIRC

No wiping with squeegee nor fingers. Just hang to dry.

jacnorectangle · Mar 2, 2016

Sirius Glass said:
Did you use stabilizer after the last wash? It should be the last chemical used. IIRC

No wiping with squeegee nor fingers. Just hang to dry.

Yes I use the final rinse last. I do squeegee it with my fingers but that's never caused any spots on my 35mm film.

RobC · Mar 2, 2016

25% vinegar means sod all. Acetic acid strength should only be less than 3% I use 1.5%. What %age of acetic acid is your undiluted vinegar? My bet is you won't know and will be guessing based on waht you've read somewhere.

And dyring marks are mineral deposits. They stick to film like s**t to a blanket. If you try and wipe them off they will scratch the film surface and they won't all come off.

If you soak the film and then very gently try and wipe them off they may come off but when you dry the film afterwards you may get some more if your water isn't really pure. Best policy is to remove all water droplets before leaving to dry.

Sirius Glass · Mar 2, 2016

You should not save money by using home made stop bath; use photographic grade stop bath from a photochemical company. That would eliminate one source of problems.

mklw1954 · Mar 2, 2016

I agree with the previous post - I must have developed over 200 rolls of film using an $8 bottle of Kodak indicator stop concentrate. A few pennies per roll is worth it.

bvy · Mar 2, 2016

There's nothing wrong with table vinegar, but it needs to be diluted to 1-2%. That's PE's recommendation, and it's what I and others here are using. As described, you're closer to 5% which could cause problems. Try a higher dilution.

Patrick Robert James · Mar 3, 2016

Those look like air bells to me.

Try whacking the tank after you fill it up with developer, and after you agitate, in order to dislodge the bubbles. Also, make sure you don't fill the tank to the brim. There needs to be some space left in it for the fluids to move around.

I don't know why you guys are bringing up stop bath. This is obviously a development issue. Also, if there were deposits on the film, the marks would be lighter, not darker.

Sirius Glass · Mar 3, 2016

When I develop in a tank, I gave the metal tank a hard tap on a thick block of linoleum [a cutting block from an arts store]

jacnorectangle · Mar 5, 2016

Patrick Robert James said:
Those look like air bells to me.

Try whacking the tank after you fill it up with developer, and after you agitate, in order to dislodge the bubbles. Also, make sure you don't fill the tank to the brim. There needs to be some space left in it for the fluids to move around.

I don't know why you guys are bringing up stop bath. This is obviously a development issue. Also, if there were deposits on the film, the marks would be lighter, not darker.

I tried whacking it. Still getting the damned spots. Maybe I wasn't whacking it hard enough. But I wonder why this never occurs with 35mm film.

bvy · Mar 5, 2016

You could sacrifice a roll and try constant agitation. I say "sacrifice" because you can't easily do that in a water bath, so your developer temperature will fluctuate. If you still see the spots, you know you're problem probably lies elsewhere.

jacnorectangle · Mar 11, 2016

bvy said:
You could sacrifice a roll and try constant agitation. I say "sacrifice" because you can't easily do that in a water bath, so your developer temperature will fluctuate. If you still see the spots, you know you're problem probably lies elsewhere.

So would that be constant inversion during the whole development? Would I need to shorten the time?

bvy · Mar 11, 2016

jacnorectangle said:
So would that be constant inversion during the whole development? Would I need to shorten the time?

Yes, slow constant inversion through the whole cycle. You could shorten the time, but it's not necessary. I follow the Kodak processing routine which is 30 seconds initial agitation and inversions every 15 seconds -- which is actually pretty "constant" already.

spots on 120 film only

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