Camera light leak or processing issue?

Question

After leaving it in the cupboard for a while, I just shot 2 rolls of B&W 120 film on my Holga and had them processed and scanned by a local lab.

I expected that I wouldn't get perfect images out of my Holga, but on both sets of negatives I am seeing weird light leak like artifact across pretty well all of the frames in both rolls of films (which I have never remembered seeing before). And these artifacts appear a lot sharper than I would attribute to a leak in the camera itself. So I am trying to narrow it down to either a leak in the camera, my film handling or the labs film handling and processing.

Here is an excerpt across the top of a single frame from both of the different films. The first excerpt is the last frame in the roll, and the second excerpt is from the middle of the roll.

The artifacts are mostly noticeable at the top of the frames, but I have noticed some frames that having matching artifacts vertically aligned on both the top an bottom of the same frame

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As requested, here are pics of the contact sheet that was produced from the negs that shows the full top of the frame. I've highlighted the areas of interest. I'm beginning to wonder if the answer to my question is ¿Por qué no los dos? Because on one frame the "leak" doesn't extend past the frame and is very symettrical (which was in the middle of the roll), but in the other a very sharp line extends up to the top of the neg, and is not symmetrical (and was the last frame in the roll)

Answer 1

That's a light leak in the camera.

With a Holga especially (but also in some 1920s vintage folders) there is limited light shielding between the frame gate and the two rolls on supply and takeup side. This is especially true if your Holga has the frame mask removed (some don't come with both 6x4.5 and 6x6 masks, so users simply remove the mask to shoot 6x6). The momentarily bright light from the shutter can scatter along the surface of the film or, even with the mask in place if it's not snapped in, along the underside of the mask, and fog the film on both ends.

In your example, there's no fogging right against the frame edges, so I'd presume your 6x6 mask is present, but not tightly installed -- and this is intermittent because it'll be most noticeable on the frames to either side of a particularly bright exposure.

Assuming you don't want to simply accept this as part of the "Holga experience" you can apply electrical or gaffer tape on the edges of the frame mask to trap light scattering under that part and keep it away from the film on the rolls.