Service Tips | Industry & Tech Information, USCamera Light Seal Material Information

When Are Light Seals Bad?

When Are Light Seals Bad?

I always tell customers to check the hinge seal 1st. If that seal is sticky or crusty, you need replace the foam in your camera. Foam in good condition is soft to the touch and will not be damaged by you touching it. Dragging a finger down the hinge seal will do nothing to a good foam seal.

How long will light seals last? Depends mostly on the conditions where your equipment is stored. Also, the pollution level in the air, humidity, temperature, and type of use your equipment is exposed to. Airtight storage is always best.
When Are Light Seals Bad?

In the early eighties, when many film cameras were being produced, we were replacing light seals on cameras mostly 7-15 years old because they were bad as in sticky, damaged, or missing.

…we see an average life of 7 – 15 years

Many seals were damaged from high humidity, as in basement storage… the worst place for camera equipment.

That being said, I have cameras in my collection, many 50 years old and the seals are like new. No signs of deterioration.

Checking your cameras foam seals is the key to preventing film fog from a light leak.

Leave the mirror cushion alone and read on.

Seals can be soft or firm to the touch depending on the density and or thickness of the foam.

The first seal I check is the hinge seal on either the back cover or the camera body. If not sticky, with light pressure, rub your finger down the length of the seal. A good seal feels somewhat smooth, stays in place, and will not roll-up. Pushing the foam flat, it springs back.

You may need a magnifying glass for this check…

Next, check the door channel seals on the body. Carefully pick at the foam with a toothpick. Nothing should stick to the toothpick. Also, with very light pressure, you can drag the toothpick in the channel. No foam residue should be present and the seals should be completely intact.

If either of those areas needs foaming. I stop checking the camera because it needs all new seals.

Mirror Cushion. If the hinge and channels seals need to be renewed, so does the mirror cushion.

Also, If you look at the mirror, where the cushion would touch it. Sometimes you can see where the cushion left some foam residue on the surface.

You do not want to touch the focusing screen with anything or let foam debris fall on it.

I never touch the mirror cushion until I am ready to replace it.
Also, that seal can just crumble as you start to remove it.  No matter how small, foam pieces on the focusing screen can permanently damage it.

The Most Common Light Seals to Check

  • Hinge seal on the back cover or body casting
  • Latch plate seal on the back cover (some cameras)
  • Channels seals on the back cover (some cameras)
  • Door channel seals on the camera body
  • Film reminder window (some cameras)
  • Door Latch Seal (some cameras)
  • Mirror Cushion

When checking your camera, replace the light seals if…

  1. The foam is sticky or gummy.
  2. The seals are hard or crusty.
  3. A seal is damaged, torn or a piece is missing. As in the film reminder window or back cover latch plate seal.

Shop all USCamera light seal kits.

Also, adding additional seals versus troubleshooting the equipment to repair a light leak issue rarely works.

Most film camera users realize they have an issue when the negatives are suddenly fogged by light. Also, sometimes light may fog just be a few exposures, along an edge or the entire roll could be completely unusable. That can easily be prevented by checking your stuff.

Rarely, though there are times when a minor part of the camera is missing and causing a light leak.

Lastly, I hope this helps you and as usual, I encourage your comments.

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About Gray

As a veteran attending National Camera's resident camera repair school in 1979, is where I found my true calling for the demanding yet extremely interesting field of photo equipment service and sales. For 25 years we grew every year. The staff and I serviced tens of thousands of film camera items, trained many technicians, met thousands of wonderful customers and truly had a fantastic time. Within 2 years of 2004, my service experience was devalued somewhat by the internet, film camera sales/service flatlined. Camera stores 50 times larger than mine were closing. I could see a new opportunity on the Internet. USCamera started as information site then became a family run internet business. Our mission remains the same, • Specialize in Vintage film equipment, mostly after 1958 • Knowledgeable • Provide quality products • Superior Service • Always available via phone - contact form – email All of us at USCamera look forward to serving you. Gray USCamera.com

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