Sinusoidal wave patterns on film?

I recently processed a roll of 120 HP5 through my Bronica EC. The back and insert are clean, rollers are clean and spin freely. I develop in stainless steel tanks with good reels. After inspecting the film, I noticed many wavy 'scratches' that run lengthwise down the entire roll. They are sinusoidal in nature and don't follow any particular pattern. The quality of my water is pretty poor (iron? silt/sand?) and my fixer was probably on it's last legs.. I'm just wondering, is anyone familiar with this? I now have a pretty simple water filter. Also, I don't squeegee my negs. It's just strange, i've never seen this before. Any ideas?

Sinusoid typically means xray damage.

Has the film been exposed to X-rays at an airport or otherwise? Patterns like that typically result from X-ray exposure.

Interesting that you say they don't follow a particular pattern. Xrays will tend to produce a perfect sinusoid, because that's the form that's produced by the intersection of a plane (the xray sweep) with a cylinder (your film on its spool). Does the sinusoid's period match the circumference of the film on its spool (about 6cm?) or the circumference on the developing spiral (about 30cm)?

Also, xrays will of course be denser, whereas scratches will have reduced density (emulsion removed). Are the lines denser or thinner? Can you see any mechanical damage (scratch) when looking under a magnifying glass/microscope/macro-lens?

Hi Phillip,

As you've concluded, x-rays will not scratch your film. How about when you cut the film into strips? Could you be dragging it along a table or some such thing?

Neal Wydra

No xrays, purchased locally and it's not even short-dated. The patterns aren't perfect, but they are very similar to dancluff's issue ((there was a url link here which no longer exists)). Sorry, I had posted without a proper search. I cut the film while it is hanging on the line. I'm going to run my fingernail along the patterns to see if they are indeed scratches, but they sure do show up under a grain magnifier as clear lines (like straight to the base) *shrug*I wondering if maybe my 20C temp for the developer, stop and fix followed by possibly much colder water for a wash could cause this? I also don't use a hardening developer (although i'm not against it, heck i'd love to toss some in)

ool.can I simulate this pattern in a microwave too?

Cold wash can cause reticulation but that looks like orange peel, not a few wavy lines. Can you post some pictures of the patterns?

A microwave will just cook your film. At 2.4GHz, the wavelength is about 12cm so there's no way you can focus microwaves to any spot smaller than a whole roll of film. And they won't expose the halides, just make things hot. Completely the wrong end of the spectrum.

BetterSense said:

Sinusoid typically means xray damage.

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MattKing said:

Has the film been exposed to X-rays at an airport or otherwise? Patterns like that typically result from X-ray exposure.

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My thoughts exactly.