Fireworks - light bands on edge of negs?

[Kevin Caulfield]

I shot my first roll of Fuji Pro 160C a couple of weeks ago, a 120 roll, all of fireworks at Darling Harbour in Sydney.

Several frames have usually two thin bands of lower density on the left edge, the outer one being the lightest, and then one next to it being slightly darker, but lighter than the rest of neg. This is not on every frame, but is on about five or six. The bands are about 1.5mm wide.

There was no obvious (at least to me) light source nearby, but the affected frames are all taken from virtually the same place. (I moved around a little bit between exposures).

Is this probably just a result of lighting hitting my lens from somewhere else?

By the way, I was using my Hasselblad 500 C/M with an 80mm lens.

 

[Kevin Caulfield]

Just looking again at the negs, there are a couple of shots with no banding with a light on the left of the frame. On subsequent shots I faced further to the right so that the light was just out of frame to the left. Could the banding be reflections from the light?

 

[bdial]

Stray light would be darker on your negatives.
Are you able to scan and post examples?

If the lines are very consistant it may more likely be a processing problem.

 

[Kevin Caulfield]

Yes, I understand that stray light would cause darker areas on negs. My thought was that the main part of the neg may have been affected by the stray light, and the bands on the edge are where the light was somehow reduced in effect. Does that make sense?

 

[bdial]

It's not too likley that stray light would darken the whole frame evenly except for a couple of sharp lines. It would mean the film was shaded by some internal part that didn't block anything from the rest of the film surface.
Light leaks usually produce blurry streaks. If they are sharply defined, then they are often caused by a reflection from some shiny part in the camera, or a shutter defect in focal plane shutters.
For Hasselblads, the common leaks are at the darkslide light trap, which would show up on the right side of the frame, I've also seen leaks from the auxillary shutter which occurred between frames.

 

[Sirius Glass]

Kevin,

You may need to change the seal on the film back. Light comes in from the right side [for example when the sun is low and to your left]. The light crosses the film plan and reflects off the right edge of the frame. However, because the image is upside down, what is on the right side of the film back is on the left side of the negative.

Post some photographs so we can verify this for you.

Steve

 

[Q.G.]

Could be a number of things. Hard to say without seeing the things.
Any chance of an example?

 

[Kevin Caulfield]

I'll try to post an example shortly. Thanks.

 

[Kevin Caulfield]

Okay, here is a digisnap of a neg. Sorry, I don't have a neg scanner. You should be able to see the outer light band on the left edge, and then one slightly darker to its right.

 

[Sirius Glass]

It looks line the light seals need to be replaced. You can have them installed by a Hasselblad repair person like David Odess [http://www.david-odess.com/] or KEH; or purchase them from B&H or KEH. Q.G. can direct you to where a good set of installation instruction are located. Remember to use the darkslide to hold the replacement parts while you reassemble the film back.

Check these out:
http://photo.net/medium-format-photography-forum/00SUFM
http://photo.net/medium-format-photography-forum/00QzZH

Steve

 

[Q.G.]

Could also be a reflection of a strong lightsource.
Something like this:

In this image the sun is just outside of the frame on the right.
Not pretty. But also not a defective light seal.

Seals need replacing every now and again though. And it can't hurt to put a fresh one in your magazine.
Steve will post a link to instructions how to change them. I dare not, because he will be mad at me for promoting the site.

 

[Kevin Caulfield]

Thanks Steve and Q.G. Q.G., that's what it looks like to me. This back is not that old (well, 1993 as opposed to my 1977 back), but maybe does still need new seals.

Okay, Steve said Q.G. would post installation instructions for seals, and Q.G. said Steve would?

 

[Q.G.]

O.K.
Risking Steve's wrath , look here.

Your back may not be that old (and it indeed isn't), but the seal in it will have needed replacing about 8x times since it left the factory. Less often if you are willing to take a gamble on its eventual failure not messing up important, non-repeatable images.

 

[Kevin Caulfield]

Thanks, Q.G. That's a good site - don't think I've seen your (?) article before, but it is well written and clearly explained.
What's with Steve's wrath about the site?

 

[Sirius Glass]

Thanks Q.G., I could not find it.

[I jerked Q.G.'s chain for promoting Hasselblad Historical a few days ago. Q.G. is a major contributor to the site.]

Steve