'rippling' problem with developing - what causes this?

[Ian G]

Hello all. my name's Ian and this is my first post here, though I have been learning lots reading for a while. This is the second time I get this sort of rippling effect, sort of concentric oval thing.
Anyone recognise it or have any suggestions about what cause it?

Thanks for any help
Ian

 

[RobC]

where are you seeing that, on the print or on the negative?

If its on the print are you printing using glass carriers above and/or below the negative and does the negative have the emulsion side facing the print, i.e. at the bottom when printing? And if you are using glass above the negative when printing is it Anti Newton glass and the right way up with the rough surface touching the negtive?
When using glass negative carriers the normal way is plain glass below the negative with the emulsion side of negative facing the lowere glass. Then Anti Newton Glass on top of negative with rough side facing negative.

But if you are seeing that in the negative and not the print then its something else. Possibly high humidity in camera or film roll which can happen due to condensation when taking opened film canister from cold (fridge) out in into warm high humidity environment. Or from cold outside into warm humid house.

 

[Ian G]

HI
my bad - it's on the negative, here's another example of it:

or:

 

[RobC]

I'd say its probably condensation on the negative roll then and/or possibly film over tightly wound onto roll. Is it 120 film and do you pull the end tab very tight (too tight) before sticking it down when you've finished exposing a roll?

 

[Sirius Glass]

Welcome to APUG

His profile says that he shoots 35mm, not 120 film. Are you using any surfactant such as PhotoFlo on the film after washing? I do not think it is a film drying issue, I just want to rule that out as a possibility.

 

[Nodda Duma]

I'd bet a case of beer that's an interference fringe. The question is where's it coming from..ie like one of the layers in the negative (poor QC) or some effect from development process. What make/manufacturer of film is this?

 

[Ian Grant]

I'd bet a case of beer that's an interference fringe. The question is where's it coming from..ie like one of the layers in the negative (poor QC) or some effect from development process. What make/manufacturer of film is this?

Emulsions don't work like that, you can never get separation between layers It's not April 1st

Looks like newtons rings from contact with glass,

Ian

 

[pdeeh]

Is this a scan or other digitisation artifact?
Is it actually visible on the negative itself through a loupe?

 

[Patrick Robert James]

Those are Newton Rings. They result from the glass of your carrier being extremely close to the surface of your negative usually on the non emulsion side but they can also occur on the emulsion side with newer thin emulsion films. Most people use anti-newton glass on the top side of the carrier which is usually the side that causes the problem.

The simplest solution is to not use a glass carrier, but then your prints might not be optimally sharp across the whole print and if you have a condenser enlarger the negative may "pop" due to the heat and your prints will not be as sharp as they could be.

The best solution is to use anti-newton glass on the top side of your carrier. If you are using a thin emulsion film and the newton rings are from the emulsion side then you have a bit of a problem if you want to stick with glass. I use coated glass on the underside of the carrier which solves the problem but can be expensive depending on the size of the glass. If your carrier is the type that has inserts, you can use the anti-newton glass on top and the insert on the bottom instead of the glass.

If you state the type of enlarger you have and what carrier you are using you can get more specific suggestions.

 

[Nodda Duma]

Emulsions don't work like that, you can never get separation between layers It's not April 1st

Looks like newtons rings from contact with glass,

Ian

Oh?

You can in fact develop fringe effects in a material without an airgap. Iridescence in soap bubbles is a common example. Newton rings in the bond gap of a cemented doublet is another. Poorly controlled or difficult-to-control coating layer thicknesses is another.

All you need is an index-mismatched layer thickness varying around same or similar order of magnitude of a half-wavelength to generate a fringe pattern. Air gap separation - while the most common - is not required. The visibility of the fringe pattern (reflection from the index boundary) is a function of the index mismatch.

OP hasn't clarified if he sees it in the negative itself or in flat-bed scans of the negative.

 

[Ian Grant]

Oh?

You can in fact develop fringe effects in a material without an airgap. Iridescence in soap bubbles is a common example. Newton rings in the bond gap of a cemented doublet is another. Poorly controlled or difficult-to-control coating layer thicknesses is another.

All you need is an index-mismatched layer thickness varying around same or similar order of magnitude of a half-wavelength to generate a fringe pattern. Air gap separation - while the most common - is not required.

It just doesn't happen There is only one final layer of emulsion on the vast majority of films, this is down to the way modern coating heads work.

Ian

 

[Ian G]

Thanks all
I see my trust in your knowledgeability was well founded.
It appears to be some form of Newton Ringiness.
I went back re-scanned and the ripplies are gone.
Way better than labourious repairs in Photoshop
All the best and I look forward to more happy posting on this fine forum.
BTW, the film is Ilford pan 100 35mm, in Ilfotec 29
Ian

 

[RobC]

so its NOT in the negative as you said it was.

 

[Nodda Duma]

Ok makes much more sense

 

[Ian G]

so its NOT in the negative as you said it was.

Correct, I thought it was but I was wrong.