Hard shadow on hasselblad negatives

reddesert

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Sirius Glass said:
The clamp covers the end of the film to keep the film flat on the film plane.
Click to expand...

I understand, but I did look at a film back (it was a Kiev 88 film back, a near Hasselblad copy). The clamp area is shaded out by the square opening in the back. Take a film back without film, pull the darkslide, and you don't see the clamp.

The clamp also doesn't explain the notches, as those are in the square opening.
 

Sirius Glass

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Pieter12 said:
Once again, thousands of Hasselblad images are printed showing the entire rebate, including the v notches. How could this clamp shadow be cropped out?
Click to expand...

It shows up in all my Hasselblad film backs covering many versions. You must have an unusual set of backs.
 

Sirius Glass

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The notches are on the other side.
 

Sirius Glass

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Pieter12 said:
I just took a quick look at some of my contact scans. Notches, yes. Clamp shadow, no.

View attachment 311934
Click to expand...

When I asked about moving the clamp more towards the edge, I was told that could not be done on my backs. Perhaps the newer back cover less of the frame. That does not explain the OP's statement that the clamp appears on two sides and only shows photographs with the clamp one one side.
 

Pieter12

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The clamp is on the insert. Maybe you can get a newer insert. Matching numbers is all claptrap as far as I can tell. I have two backs and inserts and I swap inserts all the time without ever seeing issues.
 
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Dr Dik

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Sirius Glass said:
The clamp covers the end of the film to keep the film flat on the film plane.
Click to expand...

Thanks Sirius. This isn’t a light leak, it is some kind of cast shadow. Otherwise it would be of greater density, not less.
 
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Dr Dik

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Thanks Red. It’s clearly not the clamp.
 

itsdoable

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Is there some fogging on the film? If you follow the shadow line out of the film gate, the shadow is caused by the lip of the film gate, which includes the v-notches - which is odd, as the top of the lip is rounded, so at that angle the v-notches almost disappear. Are you getting light leakage from between the body and back? That type of leak should be obvious.

If the inside of the camera body is shinny-ish, especially around the film gate, you can get a shadow caused by the lip of the film gate - this was pretty common on older Yashica TLRs. Dose the shadow disappear when it's not against sky?

Sirius Glass said:
When I asked about moving the clamp more towards the edge, I was told that could not be done on my backs. Perhaps the newer back cover less of the frame....
Click to expand...
Sirius, can you provide a image of your negative showing the clamp shadow? Because none of my backs show the clamp in the film gate. In fact, the clamp should be beyond the rails, or it would interfere with film flatness.
 
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Dr Dik

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Sirius Glass said:
No theory, real world fact. Your image only shows the clamp image on one side of the photograph.
Click to expand...

The shadow appears on the other side of negatives as well. There is an example posted.
 
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Dr Dik

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Pieter12 said:
The clamp is on the insert. Maybe you can get a newer insert. Matching numbers is all claptrap as far as I can tell. I have two backs and inserts and I swap inserts all the time without ever seeing issues.
Click to expand...

I’ve never seen a clamp that extends into the image area on any HB back.
 

warden

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Dr Dik said:
The shadow appears on the other side of negatives as well. There is an example posted.
Click to expand...
I just took a close look at my camera and back, and I can't figure it out. It's definitely not the clamp. Why the shadow areas are on both sides of the negative is a mystery. The problem looks nothing like a light leak, which would be bright and scattered in my experience. It's more of a very precise "dark leak", and only on two of the edges.

Does every frame have exactly this problem? And do different films show this issue the same way? Do the darker areas move at all from frame 1 to frame 12?

I'm trying to think of how this effect could happen after the film leaves the camera but that seems a dead end too because problems outside of the camera tend to add light to the film. And if the problem was in the developing tank I'd not expect the problem to be on both sides of the negatives and with such precise lines.

Edit: I wonder if this is a minor light leak from the sides that is slightly overexposing the film everywhere except the shadow areas? (I doubt it, but still.) You can check this by exposing a roll of film with the perimeter of the film back taped with light blocking tape. If you try this, be careful with the tape which could damage the camera if it's too tacky. If this test yields the same dark strips on the negatives then the problem is between the lens and the film, rather than a typical light leak.
 
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Mike Lopez

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Dr Dik said:
I’ve never seen a clamp that extends into the image area on any HB back.
Click to expand...

It would be one hell of a design flaw if Hasselblad had produced backs/inserts with that clamp in the film area, requiring cropping of the negative in printing (you'd no longer even have a square, unless you were to crop the frame elsewhere). But the clamp is clearly not the culprit, as is obvious from your posted examples.

What a head-scratcher (very irritating, as you say). Good luck with this.
 

Pieter12

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Could the problem lie in the body rather than the back? Is there some sort of auxiliary shutter/baffle that opens when the mirror tilts up? I only have an SWC, no mirror or anything there, but my Rolleis have some sort of baffle between the film and the mirror.
 

Sirius Glass

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Dr Dik said:
I’ve never seen a clamp that extends into the image area on any HB back.
Click to expand...



Not that most people would notice. So that puppy has been put to bed, now back to your shadow problem.
 

Pieter12

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Sirius Glass said:
View attachment 311953 View attachment 311954

Not that most people would notice. So that puppy has been put to bed, now back to your shadow problem.
Click to expand...
Not sure what you are illustrating here. Let's see the clamp showing with the insert in the back. And I see no shadow along the negative edge. If you search the internet for "Hasselblad contact sheet" you won't find a single one with a shadow along the edge. The clamp is totally hidden when the insert is locked in place in the back.

 

warden

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There are "barn doors" behind the mirror, but they open vertically so I doubt that's the issue. But I have no better ideas. ;-)

You can see them at 12:57 in this video

 

Sirius Glass

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I have never had the shadow that the OP has. My clamp barely shows as one can see in post #40.
 

Steven Lee

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@Dr Dik this must be the most fascinating "help me investigate the problem" thread I've seen online. I am now as motivated to find the cause as you are Do you mind clarifying a few things:

* Does every shot has a shadow?
* You said it shows up on both sides. At the same time i.e. on a same negative?
* Do you have another film back which doesn't have this problem?
* Is the width of the shadow consistent?
* Do you keep the camera loaded with film for extended periods of time? What do you think would happen if you load a film and quickly expose all 12 frames and then develop it?

Thanks.

[EDIT] Basically I'm thinking of a camera being stored for some time near a source of a weak radiation which slightly fogs the entire negative (or even the entire roll). But a single frame under the pressure plate would be shielded by the thick film back frame which is almost half inch of metal if penetrated sideways. If you store the camera in one of two orientations (one side towards the radiation source vs another) this would explain the shadow only on one side at a time, and only on some frames.
 
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MattKing

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It looks like the effect of some sort of vignetting mask to me.
May we see a pic of a strip of negatives, with rebates and full edges visible for all?
 

Photomultiplier

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The "clamp" lies outside the film gate and is therefore not visible.

The attached picture (low quality handheld DSLR shot with light box) shows the same kind of shadow. I already mentioned this shot some time ago in an similar discussion.
Here it was caused by an internal reflection of bright objects, in that case the sun, from the inner wall of the body. This leads to a diffuse light coming from outside the film gate and
is therefore able to cause this kind of shadow.

Root cause in my case was not using a lens hood. Blocking out the sun with a hand, body or other objects also works.
The sun was not in the picture, but within the image circle of the lens and got projected on the inner wall of the camera.
 

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reddesert

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Please let's stop talking about the clamp. The shadow on the side with notches shows the notches in the edge, therefore the shadow is of the edge of the film gate. The shadow is relatively sharp-edged, which means that the light source is nearby to the edge or well collimated; it's not some sort of overall diffuse radiation.

An image of the entire frame of an affected negative would be useful, it doesn't have to be a scan, even a cellphone pic of the negative laid on a light box (or a computer screen, etc) has been useful in the past.

Does the shadow show up most often or most strongly in pictures with a lot of bright sky, or sun outside the frame? I agree with Photomultiplier's suggestion that it is likely from non baffled light, outside the image area, reflecting off the wall of the inside of the camera.
 

btaylor

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Back in my film movie days there was a reflective artifact called “gate flare” that could occur when a strong light in or just o outside the image area would hit the polished steel film gate and cause a reflection of light onto the film. Just a thought- maybe take the lens off and open the secondary shutter doors and poke around with a penlight and see if there are any reflections noted. Maybe the chromed edge of the film guide? Good luck!
 

MattKing

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I don't see it being flare, because the negative is less exposed in the shadow area, leading to a darker strip in the print.
 

etn

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Ditto, also using 2 bodies and half a dozen backs in rotation with various films.

Are the shadows left/right or top/bottom of the negative?
Any possibility that the rear curtains of the body could be the cause for this?
 
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