I just bought a used Polaroid 405 pack film holder. Cosmetically, it appears as new. I'm not an expert when it comes to Polaroid backs, but everything seems to be working okay...except for the fact that it consistently screws up polaroids. I've tested it extensively - different batches of pack film with different exp. dates from different stores, different processing times, etc, and the same thing is happening every time: the images are washed out and undersaturated. Deliberately oversaturating the film to compensate doesn't help either, it just results in darker images that are still washy and grey.

Is this a problem with the rollers? It seems too uniform and perfect for it to be a light leak. Is this a problem with a lot of 405 backs? On the same shot, at the same f-stop with corresponding sheet film, the sheet polaroid exposes perfectly in my 545i. I really have no idea where to start troubleshooting...any ideas would be appreciated.

Okay I can't say I've had a lot of experience with a 405 back, but the rollers and guts are the same as a Hassy back and I've field stripped them many a time.

The rollers do one thing and one thing only, spread the caustic jelly evenly accross the film. If the image is even to the edges, I have a hard time believing it's the rollers. Now if there are spots and ragged edges, that's another story..

You've changed batches of packs so it's not that. And when you said "Oversaturate to compensate" I assume you mean to over develop.

It seems you got one of two problems, over exposure or flare.

You've tested with a 545i back. In the same camera? Have you shot real film (transparencies, color or B&W neg) with this camera at the same f stop AND shutter speed? how'd they come out?

What is your shutter speed and subject? Are you shooting in the day time? What film? Pro 100 or the B&W 3000 ISO?

I can imagine two scenarios:
One: the shutter is way off and you are simply over exposing good Polaroid. Test: Leave the shutter at the same point, something in the neighborhood of 1/50-1/100. Then set your aperture to one stop under expose, and shoot and pull, then two stops under. Depending onthe day, you may have to up that shutter speed to 1/250 so you don't run out of apertures.

Two: Light is getting in somewhere. Test: Set up Expose a Polaroid, and put the dark slide in. If you don't have the dark slide, DON"T PULL IT yet.
Now cover the entire camera and back (save for the lens) with a big darkcloth, even to the point of clothes pinning the bottom. Work your hand around and pull the Polaroid. Process. Check. It should be washed out.
Now since you covered the camera before you pulled the Polaroid, we didn't give the errant light leak a chance to expose the next sheet.. Now without changing anything, expose another Polaroid. Pull And check. Any better? If it is then yo've got a light leak in the belows or around the back, if it isn't then sell the bloody back on ebay and get a new one

Thanks for the thorough reply...I should have been more thorough in my description of my attempts at troubleshooting.

Here's the situation: I meter and average a scene. When shooting this scene, I use a 545i with sheet polaroid, the 405 with pack polaroid, 4x5 film holders with negative film, and a 6x7 rollfilm back with negative film. Everything exposes perfectly EXCEPT for the pack polaroid in the 405. This is all shot with the same camera and the same lens, it's a closed system. I've tried it with different light meters, different batches of polaroid as mentioned before, etc. Basically, I'm 100% sure that the only part of the system that is malfunctioning is the 405 back.

I'll try your test for a light leak, although I know the bellows are okay. I assumed that if it was a light leak in the polaroid back, it would seem a lot less uniform...maybe I'm wrong?

Worse case scenario, I WILL just sell it on ebay. It's driving me crazy.

Thanks for the thorough reply...I should have been more thorough in my description of my attempts at troubleshooting.

Here's the situation: I meter and average a scene. When shooting this scene, I use a 545i with sheet polaroid, the 405 with pack polaroid, 4x5 film holders with negative film, and a 6x7 rollfilm back with negative film. Everything exposes perfectly EXCEPT for the pack polaroid in the 405. This is all shot with the same camera and the same lens, it's a closed system. I've tried it with different light meters, different batches of polaroid as mentioned before, etc. Basically, I'm 100% sure that the only part of the system that is malfunctioning is the 405 back.

I'll try your test for a light leak, although I know the bellows are okay. I assumed that if it was a light leak in the polaroid back, it would seem a lot less uniform...maybe I'm wrong?

Worse case scenario, I WILL just sell it on ebay. It's driving me crazy.

Although I am not familuar with the 405, I have a 545 that I've barely looked at and a NPC for my mamiya RB that I've used a few times.
Unload the 405 and close it, remove the darkslide and observe the film opening and what can be seen inside the holder in this state. Install the 405 on the camera, remove the lens and board from the camera and inspect the film opening from the front standard and compare to what was observed when it was off the camera for reference. Any major differences should be invegestated especially blockage.
Now focus a mini mag to spot at 2 to 3 inches. Turn off all room lights and place the mini mag light against the back to camera seam and view from front standard while moving around the mounting. Do the same for any and all seams of the holder and the dark slide slot. You may have to rotate the light from 45 degrees to 90 to the other 45 degrees to find any or all leaks.
Charles