Dust on filter?

Pieter12 · Oct 2, 2021

This spot appears in the sky on one of my shots. Could it be dust or a spot on the filter (it's a wide-angle lens, probably stopped down to f11. It seems too regular to me for dust. Or is it a processing issue? The spot is maybe a bit less than 1/8" across on a 6x6 negative.

I increased the contrast in this one to make it more apparent:

DREW WILEY · Oct 2, 2021

It's too distinct or seemingly in focus to be a filter issue, which would be much more blurred so close to the lens itself.

RalphLambrecht · Oct 2, 2021

Pieter12 said:
This spot appears in the sky on one of my shots. Could it be dust or a spot on the filter (it's a wide-angle lens, probably stopped down to f11. It seems too regular to me for dust. Or is it a processing issue? The spot is maybe a bit less than 1/8" across on a 6x6 negative.
View attachment 286898

I increased the contrast in this one to make it more apparent:
View attachment 286899

to me, this looks lke the typical spot one gets from presoaking film prior to development. This is why I gave up on the presoak and develop directly.

Pieter12 · Oct 2, 2021

I don't presoak anymore ecxept for Bergger--their instructions call for a presoak.

jeffreyg · Oct 3, 2021

If you look at the film on an angle do you see any irregularity of the film surface? Sky picture ... UFO ??

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Steve@f8 · Oct 3, 2021

RalphLambrecht said:
to me, this looks lke the typical spot one gets from presoaking film prior to development. This is why I gave up on the presoak and develop directly.

Why does pre-soaking cause this to happen?

RalphLambrecht · Oct 3, 2021

Steve@f8 said:
Why does pre-soaking cause this to happen?

presoaking may leave waterdroplets; they soak into the emulsion locally and at these spots developer action is different than fortherest of the emulsion;hence te spots.

AgX · Oct 3, 2021

This looks to me indeed as an artefact due to a droplet, maybe at drying,
But I do not see at all how presoaking can do such. I mean people who do presoaking (to my understanding, never did such myself) fill the the tank with plain water, proceed as in regular processing, empty the tank and in succession fill the tank with developer.

Steve@f8 · Oct 3, 2021

RalphLambrecht said:
presoaking may leave waterdroplets; they soak into the emulsion locally and at these spots developer action is different than fortherest of the emulsion;hence te spots.

Thanks

Doremus Scudder · Oct 3, 2021

Water drop, probably when drying. I pre-soak all my film (sheets developed by hand in trays) to keep them from sticking together. Never an artifact from pre-soaking.

Doremus

DREW WILEY · Oct 4, 2021

I presoak 100% of the time, but have never gotten something like that. Perhaps unfiltered highly mineralized tap water could do it if particles got stuck to the emulsion awhile.

RalphLambrecht · Oct 4, 2021

Doremus Scudder said:
Water drop, probably when drying. I pre-soak all my film (sheets developed by hand in trays) to keep them from sticking together. Never an artifact from pre-soaking.

Doremus

if you take an exposed film and place a drop of water on it someplace, leave it for two minutes, then, develop normally;You will see such an artifact on he processed film.

Pieter12 · Oct 4, 2021

RalphLambrecht said:
if you take an exposed film and place a drop of water on it someplace, leave it for two minutes, then, develop normally;You will see such an artifact on he processed film.

But that is not what happened here.

Patrick Robert James · Oct 4, 2021

Looks like a bubble that didn't linger too long to me. Long enough to screw up the frame though. Gotta whack that tank.

AgX · Oct 5, 2021

RalphLambrecht said:
if you take an exposed film and place a drop of water on it someplace, leave it for two minutes, then, develop normally;You will see such an artifact on he processed film.

Yes, but how is that related to presoaking?
Unless we have it on airbubbles, but this already forms an issue with actual developing.

Or is your idea that with presoaking one may be negligent, thinking "It is just water anyway"?

RalphLambrecht · Oct 5, 2021

Pieter12 said:
But that is not what happened here.

but it simulates what might have happened.

RalphLambrecht · Oct 5, 2021

AgX said:
Yes, but how is that related to presoaking?
Unless we have it on airbubbles, but this already forms an issue with actual developing.

Or is your idea that with presoaking one may be negligent, thinking "It is just water anyway"?

Yeah!

Dust on filter?

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