Vertical Stripes Aligning with Sprocket Holes

Snowfire · Oct 24, 2021

I have recently noticed this flaw on some Delta 3200 rolls I have shot and processed. The following is part of a frame from the camera (a Lomography Spinner, a slit-scan camera.)

Exaggerating the contrast shows the features more clearly:

I see three potential hypotheses here, each with potential flaws:

1) Rotating lens cameras are known for banding caused by irregularities in panning speed. But there is no rational explanation why such features would line up neatly with sprocket holes.

2) These represent flaws in the film itself. But why would the confectioning of the film (wherein the sprocket holes are created) introduce such features?

3) The features represent flow patterns in the developer through the holes during processing. But the primary flow direction during development (with bidirectional motor agitation) is perpendicular to the features.

What does anyone think?

MattKing · Oct 24, 2021

That looks like surge marks that arise from increased developer flow through the sprocket holes.

Nicholas Lindan · Oct 24, 2021

The camera pulls the film past a slit as the camera rotates. It looks to me like the speed of the film isn't smooth. If the camera uses the sprocket holes to pull the film then jerky motion that lines up with the sprocket holes is, maybe, to be expected. Maybe the camera is defective, maybe they all behave this way.

Snowfire · Oct 24, 2021

The camera does not use the sprocket holes for this purpose.

Valerie · Oct 24, 2021

Surge marks, not a film flaw. I see this often when students are first learning to process film.

Don_ih · Oct 25, 2021

How did you develop the film? Surge marks are caused by too much agitation. My bet is this is bromide drag from too little agitation.

halfaman · Oct 25, 2021

Don Heisz said:
My bet is this is bromide drag from too little agitation.

Mine too.

Don_ih · Oct 25, 2021

michael_r said:
The strange thing in this case is that the areas above and below the sprocket holes appear to be less developed. This might have led me to go with Don’s explanation, except in that case you wouldn’t get the marks going inward from both rebates.

The mystery is only solved by knowing how much agitation the film received and what developer was used.

I see (don't know how I missed) that the film was rotational agitation (Jobo or similar). I have had similar streaking in a Jobo with developer (d76) that had been reused too many times.

mshchem · Oct 25, 2021

Snowfire said:
The features represent flow patterns in the developer through the holes during processing. But the primary flow direction during development (with bidirectional motor agitation) is perpendicular to the features.

Expand on this. Developer? Dilution? What kind of motor agitation? Camera is a novelty.

Craig75 · Oct 25, 2021

Another vote for under agitation leading to bromide drag

mshchem · Oct 25, 2021

Bromide drag requires Bromide. Empty space, sprocket holes doesn't have bromide. Still it really looks like bromide drag, so what do I know. I've had bromide drag happen using dilute XTOL developing 8x10 sheet film in a 2830 tube. Dilute or exhausted developer can show up like this.

Sirius Glass · Oct 25, 2021

MattKing said:
That looks like surge marks that arise from increased developer flow through the sprocket holes.

Valerie said:
Surge marks, not a film flaw. I see this often when students are first learning to process film.

halfaman said:
Mine too.

Craig75 said:
Another vote for under agitation leading to bromide drag

mshchem said:
Bromide drag requires Bromide. Empty space, sprocket holes doesn't have bromide. Still it really looks like bromide drag, so what do I know. I've had bromide drag happen using dilute XTOL developing 8x10 sheet film in a 2830 tube. Dilute or exhausted developer can show up like this.

The smart money is on bromide drag from not enough agitation.

Don_ih · Oct 25, 2021

However, it is hard to not have enough agitation in a rotary tank.

Snowfire · Oct 25, 2021

Agitation was continuous, motorized, reversing agitation (Uniroller) with the reel axis horizontal and the tank roughly 1/2 full. If I am still getting bromide drag under those circumstances, I truly do not understand.

MattKing · Oct 25, 2021

Don Heisz said:
However, it is hard to not have enough agitation in a rotary tank.

Unless it isn't rotated continuously.

Don_ih · Oct 25, 2021

Snowfire said:
Agitation was continuous, motorized, reversing agitation (Uniroller) with the reel axis horizontal and the tank roughly 1/2 full. If I am still getting bromide drag under those circumstances, I truly do not understand.

What is the developer? It might be dead or too diluted.

mshchem · Oct 25, 2021

Snowfire said:
Agitation was continuous, motorized, reversing agitation (Uniroller) with the reel axis horizontal and the tank roughly 1/2 full. If I am still getting bromide drag under those circumstances, I truly do not understand.

Not enough active developing agent to overcome the bromide produced in development. As in dilute XTOL or even D-76. If you are using a Jobo tank with less than 100mL of XTOL stock solution per roll. I had this happen with 8x10 film. Now I use stock or replenished XTOL, (still stock ) with rotation, no troubles. If it is bromide drag, and you are agitating properly.......?

I have had bromide drag once, 2 sheets of 8x10 Tri-X. Lesson learned!

Snowfire · Oct 25, 2021

Developer was Microphen, full strength, fairly fresh and used one-shot.

Lachlan Young · Oct 25, 2021

michael_r said:
It’s not bromide/by-product drag with continuous agitation. Doesn’t make sense. And if the film is rotating how would you get lines perpendicular to the direction of rotation?

It may be stress-marking from rewinding the film into the canister the wrong way - though the effect is often stronger than this. Mind you, I've found Delta 3200 to be surprisingly resilient to stress marks, given what are likely quite big flat Delta crystals.

mshchem · Oct 25, 2021

May be one of the great mysteries, like Bigfoot or mild Ghost peppers

Don_ih · Oct 26, 2021

Some things to try:

(1) try a different film in the camera with same developing method. (test camera)
(2) try the same film in a different camera with same developing method. (test film)
(3) try the same film in any camera with the same developing method. (test developer)

and likely all will be revealed.

Craig75 · Oct 26, 2021

If the tank is on its side then the bands are going the wrong way for either drag or surge marks surely.

One would think then that the only other cause has to be the movement of slit across film in camera.

Just looking online you can see a number of shots posted with it have banding. Even the sample photo on lomo own shop has banding in it.

Kino · Oct 26, 2021

Snowfire said:
1) Rotating lens cameras are known for banding caused by irregularities in panning speed. But there is no rational explanation why such features would line up neatly with sprocket holes.

I would vote for panning/film advance speed variations; even at least one of the samples on their web page clearly shows these bands in the image. The varying slippage of the film in the light trap of the 35mm film cassette when it hits a pair of perforations could account for this under certain situations, like high humidity or older film stock that has set in higher humidity.

https://shop.lomography.com/en/spinner-360-new-package?country=us

Also, it looks like the negatives are very high in density, which indicates a high processing gamma, which accentuates any exposure variations in otherwise uniformly exposed patches of negative.

Try lowering your exposure and developing to a lower density.

PS: Just think what would have happened if that guy on the plane who got taken down for messing with his camera had pulled out a Lomo Spinner!

Neal · Oct 26, 2021

Light leak. (I just wanted to make sure every conceivable cause was mentioned.)

Snowfire · Oct 26, 2021

Kino said:
.
Also, it looks like the negatives are very high in density, which indicates a high processing gamma, which accentuates any exposure variations in otherwise uniformly exposed patches of negative.

Try lowering your exposure and developing to a lower density.

The negatives are not high in density--they are in fact a bit underexposed, though I tried to compensate for that in scanning. You see, this roll was shot through a B+W 403 visible-blocking filter, which reduces the effective ISO to the 50-100 range in daylight. The Spinner has only one exposure time and a choice of f/8 or f/16--not much control there, and the stock configuration is better optimized for films in the ISO 200-400 range. So the exposure is a tad suboptimal but the best I can manage. The near-sunset conditions probably contributed to the underexposure.

I do have one roll that was shot in a different camera but processed similarly. I also have some color rolls (processed commercially) that were shot with this camera. I don't recall seeing this in either, but I should go back and check more closely. Mechanical binding of the sprocket holes on the cassette lip could produce bands of the right frequency--but the precise alignment would have to be some kind of amazing coincidence.

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