Hasselblad 500cm light leak help

[Ariston]

Happy Thanksgiving!

Is this from the light trap on the back, or the auxiliary shutter? It is confusing because the light leak doesn't come from the very corner of the frame. Thanks for the help:

EDIT: I should mention that this only happened on two frames. Once I was holding the camera over my to get a shot, and the other was this one, with the back faced up toward the sun:

 

[gorbas]

It's most likely from old and worn magazine light seals, where you insert dark slide on the magazine.
It will be great if you can include in your picture entire negative with margins?
Generally I'm trying never to leave dark slide in the magazine while camera is in storage mode. Dark slide left in magazine ruins light seals much faster. YMMV
With new film inserted, put black electrical of gaffer tape over the dark slide slot and try it again in bright sun.

 

[Ariston]

It's most likely from old and worn magazine light seals, where you insert dark slide on the magazine.
It will be great if you can include in your picture entire negative with margins?
Generally I'm trying never to leave dark slide in the magazine while camera is in storage mode. Dark slide left in magazine ruins light seals much faster. YMMV
With new film inserted, put black electrical of gaffer tape over the dark slide slot and try it again in bright sun.

Thank you. This camera is new to me, so I haven't done any long term storage yet, and it is good to know I should leave the dark slide out. I took the magazine apart, and the light trap seemed ok, but the foam was pretty aged. I thought about putting some felt where the foam is, but was worried it would be too thick...

 

[GLS]

I thought about putting some felt where the foam is, but was worried it would be too thick...

You can buy pre-made kits for replacing the light seals in Hassy film backs. They're fairly cheap and easy to install youself:

https://www.ebay.co.uk/itm/HASSELBL...335890?hash=item56c8570e12:g:9OkAAOxy~g5RppHh