I have several rolls with similar light leaks such as below, but more examples here and here.

These rolls are all bulk loaded, in recycled canisters (meaning rolls that came from a lab which new film was spooled into). The leaks appear in various cameras that have not shown issues with other, non bulk loaded rolls. Additionally, the leak is always in the same spot on the frame. This last point is not limited to full frame, as the last linked example comes from a Hasselblad X-Pan.

The facts:

  1. The leak is most likely occurring in-camera due to the consistent spacing with different frame sizes
  2. There appears no gradation in the intensity of the leak across the roll
  3. The leak does not move across the roll
  4. There is a distinct S-shape recurring in all instances

Any idea what could cause these artefacts? I am puzzled, as I would think a canister with shot up light seals would be leaking light outside of a camera just as much.

enter image description here

  • \$\begingroup\$ Further, a cassette with bad velvet wouldn't leak inside the camera -- it's dark in there. You've got a puzzler here. \$\endgroup\$
    – Zeiss Ikon
    Mar 17, 2022 at 16:45
  • \$\begingroup\$ @ZeissIkon it's only dark to a certain extent. Some cameras have windows, and I wonder if this issue is specific to that. And of course there's a certain burst of light that happens with photography ;) \$\endgroup\$
    – timvrhn
    Mar 17, 2022 at 18:53
  • \$\begingroup\$ Bad light seals on a film reminder window would leak on commercial rolls, not just reloads, and the intentional exposure wouldn't overwhelm other exposures on the film. \$\endgroup\$
    – Zeiss Ikon
    Mar 17, 2022 at 19:01
  • \$\begingroup\$ Can you try loading some rolls in cassettes made for bulk loading, instead of reused commercial ones? Looking at these, I wonder if it isn't chemical fogging from something in the velvets on the cassettes you're getting from the lab. \$\endgroup\$
    – Zeiss Ikon
    Mar 17, 2022 at 19:06
  • \$\begingroup\$ @ZeissIkon I'm not suggesting the window's seals are bad (which I confirm are in great shape). At this point all my logical options are exhausted, so I am looking at anything. These windows are a source of light, so a possible though unlikely source of leaks \$\endgroup\$
    – timvrhn
    Mar 17, 2022 at 20:30

3 Answers 3


After a lot of sleuthing, it was discovered the light leaks are caused by the transparent coating on the bulk loaded labels.

These leaks were only present in cameras with a film confirmation window. Regardless of the condition of the seals around this windows, leaks would show in almost every frame. Covering this window would instantly prevent these leaks from showing. It is thought that the coating facilitates light piping, circumventing the light seals around the confirmation window.

  • \$\begingroup\$ @ZeissIkon, thank you for your help \$\endgroup\$
    – timvrhn
    Mar 22, 2022 at 20:55
  • \$\begingroup\$ @BobMacaroniMcStevens, thank you for your help \$\endgroup\$
    – timvrhn
    Mar 22, 2022 at 20:55
  • 1
    \$\begingroup\$ Great job sleuthing out the issue! Thanks for posting the answer. \$\endgroup\$
    – scottbb
    Mar 22, 2022 at 22:40
  • \$\begingroup\$ That's one I haven't seen before. Seems like plain paper gum-back labels (or just tape with hand written data) would be superior (or use cameras that don't have built-in light leak windows). \$\endgroup\$
    – Zeiss Ikon
    Mar 24, 2022 at 14:13
  • \$\begingroup\$ @ZeissIkon true. I am looking into having my supplier switch to a matte coating or no coating at all. Writing hundreds of labels each month is a little bit too laborious \$\endgroup\$
    – timvrhn
    Mar 24, 2022 at 21:36

Same place on every frame suggests the take up spool side of the camera to me.

The consistency of light leak intensity and complete exposure are also consistent with that edge of the camera. It doesn’t look like an exposure artifact.

The s-shape suggests a bowing in the film in the sprocket hole to sprocket hole direction.

A possible cause via bulk loading would be how the bulk film is attached to the spindle or old leader. My experience is the amount and orientation of the tape is important to smooth operation of bulk rolled cartridges.

[edit] worth noting the Xpan spools all the film out of the cartridge and then “rewinds” each frame into the cartridge when exposed. This behavior means that a problem with the hinge seals would leak light onto the film before exposing a frame rather than afterwards. This has implications for troubleshooting procedures.

[edit] I googled "Xpan light leak." This Reddit thread looks like a light leak in the same location on an Xpan. This Flickr post about an Xpan light leak also looks similar. These pictures linked from this Reddit thread have a similar Xpan light leak.

  • \$\begingroup\$ Problematically with this explanation is that the leaks show up on different cameras with different frame sizes that show no issues on other films. Additionally to that, there is a definite lack of leak intensity, with sometimes the leak barely being present at all. However, especially considering different frame widths have the leak show up in the same place seems to indicate the space between canister and film gate to me \$\endgroup\$
    – timvrhn
    Mar 18, 2022 at 6:52
  • \$\begingroup\$ To reply to your comment about taping the film to the canister: using scotch tape I attach new film to the leftover film still sticking out the canister along the width of the film. As far as I can tell, and I've shot rolls myself, everything runs smoothly \$\endgroup\$
    – timvrhn
    Mar 18, 2022 at 7:00
  • \$\begingroup\$ @timvrhn intensity of a hinge side light leak will very with the amount of time ‘the next frame’ sits next to the hinge and the intensity of the light. If it is shot a few seconds after the previous frame in indoor light, the light leak may not be visible. If the next frame sits twenty minutes on a tripod in full sun it can be baked in fully. \$\endgroup\$ Mar 18, 2022 at 17:13
  • \$\begingroup\$ @timvrhn My understanding is the Xpan can shoot both panoramic and 3:2. But what are the other cameras? \$\endgroup\$ Mar 18, 2022 at 17:14
  • \$\begingroup\$ @timvrhn scotch tape traveling through the canister felt has created issues for me, though I use reloadable canisters. Now I use gaffers tape and not so much it passes through the felt. \$\endgroup\$ Mar 18, 2022 at 17:17

Bulk loading film as its share of perils. Bulk film comes to you in a light-proof wrapper packed in a light-proof metal or plastic canister. Today’s films are likely panchromatic (sensitive to all colors) thus no safelight can be uses (exception – a dim green far distant might be OK). Best if no safelight is used.

You must unpack and unspool the film in total darkness. A darkroom that is totally dark is hard to find. You may think its safe but after being in total darkness for about 20 minutes you might change your mind. The human eye will dark-adapt over time and you might discover that some of the dark has escaped.

Assuming your work area is safe, now you go to work. You strip off a meter or so and spool this into a cassette. Is the cassette light-tight? Many a roll has spoiled due to risky cassettes. Also, the base of the film can allow light piping. That’s light entering the cassette via the clear film base. 35mm film often has a gray base to fort light piping. Some have an opaque backing called a remjet (removable jet black). This is lampblack carbon coated using an adhesive that softens in an alkaline developer.

Often work using a bulk loader. This is a light proof spooler that we load in total darkness. Sometimes the bulk loader allows the dark to leak out. I could go on and on about the different dangers but likely you have experienced some of these threats.

  • \$\begingroup\$ I've bulk loaded close to 4000 rolls, the majority of which indeed with a rEmjet layer. Very interesting stuff, and definitely noticed the many steps at which light can be introduced. An interesting one is static discharges, occurring frequently on/in the black light bags the bulk rolls come in. Frustrating! \$\endgroup\$
    – timvrhn
    Mar 24, 2022 at 13:36
  • \$\begingroup\$ This talks around the already accepted self-answer. \$\endgroup\$
    – Zeiss Ikon
    Mar 25, 2022 at 11:00

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