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What did I get wrong about the Hasselblad A12 light seal installation for my 500C?

Certain Exposures

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Hi folks. I could use some of your advice. What did I get wrong about the Hasselblad A12 light seal installation for my 500C? I added a fresh set of dark slide seals. However, there's still a light leak. It's not in every frame. I followed the instructions in these videos: 1, 2.​


Someone on Reddit claims there are additional light seals that could require replacement. I have not run into information about these additional light seals yet. Do any of you have information about them?

Thanks in advance for any insight you may have.

Test frame with a light leak circled in yellow:




Pictures of my light seal replacement job:



Suggestion that there are inner seals that could require replacement:

 
22, 25, 28, 35 are also light seals. Did you replace 41? You have the foam sitting in 37? The light seal at the dark slide is the one that suffers the most, since the slide gets put in and removed. The other seals likely have probably fossilized, but they're also possibly still doing their job if the back has never been taken apart. The light leak you have looks like it's coming from the dark slide. The slot 41 fits into needs to be cleaned out completely before replacing it, or it can get caught by the dark slide and pushed out. And you fit the foam into 37, right?

People like to stand at their pulpit and wag their finger. But the fact is, most of the time a Hasselblad light leak is fixed by buying one of those cheap kits. Take it apart again and see if anything looks wrong.


 
I had a similar light leak on my back. It's not caused by the dark slide seals but most likely by the seals no. 28 outlined by @Don_ih. I think I changed 22 as well. No tutorials online but it wasn't very difficult.
 

Thank you.

Yes, I replaced 41. The foam is sitting in 37. I included pictures of both underneath the test frame. The thumbnails might be a bit hard to see unless you click on them. Once you click they should expand. 41 is no more than a millimeter shorter than the cavity (click the middle picture). Could that be the cause?

I took those images above of the replaced seals after I tested them and still noticed a leak.

OAPOli said:
I had a similar light leak on my back. It's not caused by the dark slide seals but most likely by the seals no. 28 outlined by @Don_ih. I think I changed 22 as well. No tutorials online but it wasn't very difficult.
Click to expand...

Thank you. I have several questions.

Where did you get the foam to replace those seals? Did you require any special tools aside from the ones you already used for the dark slide seals? How long did it take you? Did you take pictures of the tear down and reassembly?

If I'm not mistaken, the leak tends to appear on the opposite side of the problem seal. If that's true then the orientation would suggest that 28 is the culprit.
 
Certain Exposures said:
Where did you get the foam to replace those seals? Did you require any special tools aside from the ones you already used for the dark slide seals? How long did it take you? Did you take pictures of the tear down and reassembly?
Click to expand...
Camera light seal set made in Japan 5pcs, 1 to 3mm from Amazon; no; not very long; no.

It was 1.5 years ago so I don't remember the details, only that it was straightforward.
 
@Don_ih , @OAPOli and anyone else that may be reading, are heavy cloud cover days sufficient for checking for light leaks in your experience?

I have a new film back to check. I've always waited for a clear sky because I assume direct sunlight is a better test.


By the way, I readjusted the dark slide seal in the film back I started this thread about (quote above) and did a "test"* roll with all exposures 1/60 or slower. I saw no light leaks - even in a few backlit frames with reflective objects. However, the "test" was indoors. I have to do an outdoor test roll of the fast speeds another time.

*Not truly a test. I used the back out of necessity and tried to work around its suspected issue.
 
Last edited:
Thanks, what's your approach to using a flashlight as a test during the day? I want to check 1/125 - 1/500th. I question if my small speed light is bright enough to trust.
 
If you're looking for a light leak, put some film in the back, remove the darkslide, shine a light all around the back. The shutter has nothing to do with it. The back can leak light through the darkslide slot (most common) or possibly around where the gear meshes with the camera (unlikely) or maybe just by being a bit loose in the attachment to the rear of the camera (unlikely).
 

Update:

I haven't developed the second test roll yet because I had to slow down for a while. However, I did purchase another A12 back from a retailer that checks their equipment. Unfortunately for me, it has a light leak, too! Thankfully, I can return it.

I have not had the luckiest introduction to the Hasselblad system.
 
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