Help solving film holder light reflection

[nlambrecht]

I am looking for suggestions for solving what I believe is a light reflection off my Fidelity Elite film holder onto the film when using wide angle lenses (please see photos below). When shooting an image with a strong out of frame light source occasionally I will get a highlight on the film. I know that more accurate placement of a hood or french flag would help this, but I am also considering painting the edge of the film holder with an ultra matt black paint to help as well, such as black 2.0 (https://www.culturehustle.com/collections/potions/products/black-v1-0-beta-the-world-s-mattest-flattest-blackest-art-material). I am wondering if anyone has tried this before, or has a suggestion for something I may be missing. Thank you.

170570
170571

[xkaes]

It could be a lot of things. Can you see it in the scene? Does it only happen with one holder?

Better to determine the cause than using "trail and error" approaches to a solution.

[Leszek Vogt]

If this is an extended exposure (and it looks like it is), you may have a strong/er light reflection from some source. But, that requires a test or two to make sure it's not the holder. Hard to say from here.

Les

[nlambrecht]

This light only occurs when I am shooting with my 90mm when there is a strong light source outside the image on the film. In this case it is a bank of windows to the right of the frame. I use wide angle bag bellows frequently and in no other images have had light leaks. Additionally, this will sometimes occur on any side of any Fidelity Elite holder, other than the side with the film loading door. For this image I exposed three sheets in two holders, all images have the same light on them. It was about a minute exposure with reciprocity adjustment, but I have had it occur on shorter exposures. I use other wide angle lenses without this problem, a 58, 75 and 120.

Since the light will come out occasionally regardless of direction of the film holder (i.e. vertical, horizontal from left or right insertion), direction of light source (above or the side), or holder used, I believe it is a reflection of light off the slightly reflective surface of the holder. I am thinking about finding a way to dull the reflective surface, one method may be mat black paint. I am wondering if anyone else has attempted this, or solved this problem another way. One problem with mat paint it is notoriously brittle and may cause a dust problem.

Of course, I probably shouldn't put strong light sources next to the image area, but hey what can I do?

[Jim Andrada]

I think you could also just roughen the edges of the holder with a little very fine sandpaper, being sure to clean well afterwards. Unlike paint it won't flake off

[Tobias Key]

Looking at it closely, there seems to be an image of a window or banister within the light leak, that would indicate a pinhole. Have you tried draping your dark cloth over the bellows during exposure?

[xkaes]

Looking at it closely, there seems to be an image of a window or banister within the light leak, that would indicate a pinhole. Have you tried draping your dark cloth over the bellows during exposure?

Or natural reflection from window glass.

[LabRat]

Sure looks like a light leak, with some pinhole or gap forming an image... You can try "exposing" and developing a sheet of B/W, while placing the bright source near the edges (at your normal focusing distances) and looking for fogging without firing the shutter to check... Or a thorough flashlight bellows/body check... (Or a "sun test" with a piece of film loaded in camera, sitting out in the sun for awhile...) And check where lensboards/backs/standards/bellows connections/film holders seat very carefully... # your filmholders and note what shots have the fogging, and check...

Sometimes light will leak at only one narrow angle (that does not happen to line up too often), but when the evil planets align, ...

Steve K

[Kirk Gittings]

Sure looks like a light leak, with some pinhole or gap forming an image... You can try "exposing" and developing a sheet of B/W, while placing the bright source near the edges (at your normal focusing distances) and looking for fogging without firing the shutter to check... Or a thorough flashlight bellows/body check... (Or a "sun test" with a piece of film loaded in camera, sitting out in the sun for awhile...) And check where lensboards/backs/standards/bellows connections/film holders seat very carefully... # your filmholders and note what shots have the fogging, and check...

Sometimes light will leak at only one narrow angle (that does not happen to line up too often), but when the evil planets align, ...

Steve K

agreed

[nlambrecht]

I did a bit of testing of my theory and it is a reflection off of the Fidelity Elite film holder when there is a very bright light source not hitting the film area, but striking the perpendicular ledge on the film holder. Every now and then I frame something with a bright light source out of frame, this has happened on only 4 scenes in the past 3 years of about 700 negatives I have shot in that time - so it is rare, but as LabRat said, "when the evil planets align." I will take the camera and demonstrate this with a video and a flashlight on Monday. Below are details of the other three negatives that this occurred on. Better use of a hood or french flag should help, but the tolerances are tight. Now what I need to do is figure out if I can dull the ledge so this does not happen, any thoughts? (FYI, this did not happen on the same holder, my field notes state that this occurred on 5 different Fidelity Elite holders).

170603 Large light source directly behind tree, with open canyon behind

170604 brighter light coming from top of slot canyon

170605 dense trees thin out with sun rising in background

To be fair, a slight reflection also occurs off the black paint inside my Shen Hao HZX 45iiA that is near the film holder, but that is almost always hooded or flagged off.

Also, square shape on the original post photo is coming through the window from another reflection outside, it was on the wall when I took the photo. I know it kind of messes up the conversation since it is there.

[ic-racer]

I guess I'm not seeing it. Do you mean the light reflects from the edge of the film holder, skips a few millimeters and then exposes the film? I'd check the camera. If the film holder is edge is 2mm and your fog starts 2mm from the edge of the film holder, the light is striking from a 45 degree angle from some place in the camera. You should be able to find it.

[LabRat]

OK, but it does look a little broad to be just an internal reflection, as it would take a larger surface to reflect enough to create that much fogging (and a bright one at that)...

But in your overall search, you can try to put your camera in a darkened room with either the lens on/shutter open, or leave a cut-out lensboard on, remove the GG panel and/or back, and have someone or a stand with a very bright flashlight or photo light, and view through the back while the light is just off-axis shining towards the front lens or hole, and see if any plane inside the camera has a bright glow that might be reflecting towards the film... You can apply some felt or other non-reflective material or paint there, but if the area is not a real "hot" spot, I doubt it could reflect enough to create the type of density you have there (I think it would almost take something shiny in the camera to do that)...

So you are certain there is no loading/film storage issues??? I still think there's a leak somewhere...

Happy Hunting!!!

Steve K

[Neal Chaves]

Reverse the camera back so you load the holder from the side opposite the light source. Be sure to put the slide in straight, not one corner first which will open the light trap.

[nlambrecht]

Do you mean the light reflects from the edge of the film holder, skips a few millimeters and then exposes the film?

That is correct, I will try to shoot and link to a video tomorrow. It is odd, but only occurs when a bright light is near the edge of the frame.

[Doremus Scudder]

Nathan,

I'm going to put my money on a pinhole or other small light leak as well. After carefully looking at your photos and thinking about it a lot, I rather think it is not attributable to reflections from an edge of the film holder. In the past, I have had lines of extra density on the negative, parallel to the 45°-angle edge on the face of the filmholder. These I figured were coming from the 45°-angle edge on the filmholder and, indeed, a little sanding fixed the problem. Comparing my marks with yours: mine were very thin and long and had nothing in them that looked like "image," i.e., no detail, just added density. Your problem is a lot broader and has detail, plus, it is not taking up most of the length of the negative, rather is limited to a smaller area, like that that would be projected by a pinhole.

I'd check the bellows, of course, using a bare bulb inside the camera with the bellows extended all the way as well as the camera back, the seat and the holder itself. I've had a holder or two that needed to have the small slot between top and sides filled because they were leaking light a bit.

Good luck finding your problem,

Doremus

[Fred L]

I'd put my money on a light leak vs reflection off holders. I've never seen this with any of my old, or newer 4x5 or 8x10 holders. Only time I had problems was a bellows pinhole in a Wista 4x5. ymmv but I'd also be looking at the fit of the back or bellows to the rear standard vs film holder reflections.

Hope this can be figured out.

[nlambrecht]

So today I made a quick video to perhaps better explain what is going on and demonstrate my findings. You can find the video on Vimeo here:

https://vimeo.com/237498021

Once again this is a rare problem, only showing its' ugly head a few times out of a lot of negatives, but that it exists bugs me.

Thank you to all who have taken the time to make suggestions, additional suggestions are greatly appreciated.

-Nathan

**Edit - wow, videos embed!! Wonderful!!**

[biedron]

That demonstration appears to lend some plausibility to your theory. Seems like Ben Horne feels he had a similar issue with Fidelity holders. See around the 1:30 mark here:

https://www.youtube.com/watch?v=dNA1jvAFUUQ

Bob