Help identifying light leak (images included)

[Rhemz]

Hey guys,

I'll start off by saying i'm very new to large format photography. I've shot digital for about 7 years and decided to give LF a go a few months ago. I assembled a modest setup consisting of a Tachihara 4x5, a Rodenstock 90mm 6.8 & a Schneider 150mm 5.6. I took went on vacation to Cape Cod a few weeks back and took it as an opportunity to spend some serious time getting acquainted with the view camera.

I took 12 exposures (velvia 50) while I was there, and got them developed last week at a local shop. Unfortunately, it appears i've got a serious light-leak somewhere and every exposure came out with similar burn marks. The guy at the shop seemed knowledgeable and said it looked like a leak in the bellows, probably towards the back of the camera; I found that peculiar as the Tachi is new, and i've spent the better part of an hour checking it in my dark room with a flashlight to no avail. I'm using Fidelity Elite and Fidelity Custom film holders, and the burns are of similar shape and location regardless of which holder I used, which makes me think it's not a leak in the holder.

This, combined with the consistent shape/position of the burn mark(s) makes me think the leak may be coming from either
A) where the back attaches to the camera body, or
B) the contact between the film holder and the camera back.
I'm currently leaning towards B, as it's contact between a ridged plastic surface and glossy cherrywood.

I've noticed that while the camera back & body fit snugly and the contact strips are painted matte black, there is one thin strip where it is unpainted. I plan on picking up some black paint today & painting over it just to make sure. As far as the film holder->camera back issue, I was thinking of picking up a sheet of black velvet & gluing it to the camera back as a light-proof buffer between the holder and the glossy wood, but before I started gluing and painting my camera I thought it would be prudent to get some opinions from the seasoned pros (you guys :D ).

Here are the images:

http://www.be-logic.org/uploaded/1_img001.jpg

http://www.be-logic.org/uploaded/1_scan3_lightleak.jpg

Following my assumption of B: These are both horizontal images, with the burn marks showing most prominently in the bottom-left of the image, meaning the leak is worst at the top-right of the camera back. I load my holders in from the right (darkslide comes out on the right side).

In this vertical image, the film holder was loaded from the top (darkslide pulled up & out):
http://www.be-logic.org/uploaded/1_scan2_lightleak.jpg


I would very much appreciate some expert opinions, as I'm very new to this and don't want to start gluing and painting my camera unduly.

Thanks very much guys. I really hope I can resolve this issue without too much headache -- I thoroughly enjoyed my time with the view camera so far.

-Russ

[pablo batt]

what is your film loading and removal process?

[Rhemz]

The film was loaded & unloaded in complete darkness. It was done in a small, sealed room inside another sealed, windowless room. I don't think the leak was happening at this point. There is a correlation between the intensity of the leak marks and how bright it was when I took each shot.

[pablo batt]

could also be the position of your film holder in the back,

most important to get the film holder located into the small slot on the camera or it will be allowing light to slip in under and at one end of the film holder

[Rhemz]

I just took some shots of the camera back & film holder. Please tell me if I'm loading it improperly:

http://www.be-logic.org/uploaded/1_cameraback.jpg

When the holder is fully inserted, the flat edge of the left side fits snugly against the recessed plane on the left side of the back.

[Mike1234]

Could also be holes in the bellows or at its mounts. Take the camera into a dark room and shine a flashight throught he lensboard opening to look for leaks. Are all of your film holders the modern plastic variety?

EDIT: Or you could have a light leak at the lens board too... or around the lens.

EDIT #2: The shape and location of the fog is a bit perplexing... looks like it's shaded (blocked) on all four sides by the holder. This leads me to assume the leak is at or very near the back of the camera.

[Rhemz]

Could also be holes in the bellows or at its mounts. Take the camera into a dark room and shine a flashight throught he lensboard opening to look for leaks. Are all of your film holders the modern plastic variety?

The bellows have been tested thoroughly & i've found nothing. I've tried with and without lensboards/lenses. Half the film holders are plastic, half are metal. The burn marks are the same regardless.

Also, if it were in fact the bellows or lensboard, I don't think the position of the marks would change along with the orientation of the camera back. Correct me if i'm wrong.

[Mike1234]

Check my edit #2... suspect the leak is at the back of the camera.

EDIT: Check the fitting of the back to the camera.

[Ari]

Mike,
Have you considered your film? Is it possible that you got a bad batch, or that it somehow got partially exposed?
If you haven't already done so, I suggest opening a fresh box of film and trying that.
These things are never pretty.
Good luck.

[Rhemz]

Ari, I had not actually considered that. I'm not sure how likely it is, as the shots were spread out over 2 different boxes of film & the results are the same regardless.


-Russ

[R Mann]

I think you are correct to rule out the bellows because of the change in position of the back and the resulting leak pattern. To me it looks like your option B - a leak between the holder and camera. Are you sure you are getting a tight fit when the holder is inserted? In the photo it looks like your groove is at the edge of the opening, is there wood missing on the camera back on the left side of the groove? Or, have you checked the fit on the camera back and the body? Any gaps there?

[Louie Powell]

Two of the three sheets you have shown us have fogging in the lower left corner, which means that it's in the upper right corner when the back is on the camera. I think it's also important to observe that there fogging is completely inside the frame - that is, there is a narrow field around the outside edge of the sheet that appears to not be fogged. That causes me to agree with Mike that the problem is near the back of the camera, and that the fogging light is striking the film at a severe angle such that the edge of the holder is shading the edge from fogging.

I presume the Tachihara has a removable/rotating back. How is the back attached? It appears to me that the leak is in the area where the bellows attaches to the back. I'm not familiar with the Tachihara, but in my camera, there are clips at the upper right and left corners of that hold the back tightly against the box frame, and therefore against the back frame of the bellows. I would look either for something loose in that area, for a separation between the bellows and its frame, or for some kind of obstruction that keeps the back from seating properly on the camera.

The third sheet ('portrait' format) shows fogging on both sides and the top, suggesting that the problem is more severe when the back is rotated to the vertical position. The main thing I would conclude from that observation is that it has something to do with how the back is attached.

One other possibility - you mentioned that you have both wooden and plastic holders. Modern holders have a ridge at the darkslide end that fits into a groove machined into the camera back. But there are older holders out there that have a groove in the holder that is supposed to mate to a ridge on the camera. Can you confirm that you holders and camera match? Absent that proper mating, it's possible for the darkslide end of the holder to be loose.

Finally, try this test: load an empty holder into your camera, and then withdraw the darkslide. Watch the back very carefully to see if the effort involved in pulling the darkslide inadvertently also pulls the back away from the camera. Look at both the place where the removable back attaches to the camera, and also the point where the holder fits against the back of the camera. I had this happen with a Polaroid holder and concluded that the problem was that the darkslide handle didn't protrude far enough to be able to get a good grip on it, and as I tried to stick my thick fingers under the handle, I was inadvertently pulling the holder away from the camera at the same time that I was pulling the darkslide.

(The first sheet was Point of Rocks Beach in Brewster, right?)

[jim kitchen]

I get those light leaks periodically at the bottom of my negative, and along the sides of the negative, where it is always my fault. The film slides tend to creep up just enough to annoy me, and expose the film whenever I place the film holders too tightly into my backpack, therefore exposing the bottom edge of the film. The side leaks occur whenever I place my fingers onto the film slides too firmly, allowing a minor gap to occur, where minute traces of light tend to expose the long edge of the film. Realizing that, I taught myself to hold my film holders along the outside edge to avoid the side leaks, and I taught myself to lock the film slide in place, rather than not.

I would happen to guess that you periodically hold and transfer your film holders, while grasping the film slides, possibly causing the light leaks... :)

Just a thought.

jim k

[robert fallis]

you say that it's spread over 2 boxes of film. if it only happens with random sheets then I would suspect one of your film holders.don't use expensive film cut some black and white paper to size, you can do it under a red safe light, number your film holders and the paper so that you can match them,
and expose.. this will enable you to locate the holder with the problem

bob

[Nathan Potter]

Looks like an issue associated with the back of the camera.

Check that the holder seats tightly under the Ground Glass by placing a holder in the camera. Then in a bright room peer in thru the lens board (sans lens) and look for any light seeping in around the edge of the holder. It helps to place a piece of white paper instead of film in the holder then slipping the darkslide most of the way out. Look very carefully letting your eyes adjust to the dark interior of the bellows. Try a high intensity light close to the edge of what should be a light tight connection between the back and the holder face.

As mentioned above check for the presence of a ridge on the holders that is intended to sort of snap the holder flat against the camera frame. Practice loading the holders with no film so you get the feel for it.

Make sure your darkslides slip easily in the holders. My guess would be that you are inadvertently lifting the holder ever so slightly while moving the darkslide out or back in.

Nate Potter, Austin TX.

[Maris Rusis]

I checked my Tachihara 45GF and the same sort of film holder as you use and it appears from your picture that the film holder is correctly inserted. If the film holder is fully in and the light trap groove is engaged then the problem must be somewhere else. And I suspect it is film holder movement when withdrawing or replacing the dark slide. That was the mistake I used to do until I changed my routine. This is what I do now:

After I put a film holder into the back of the Tachihara I make sure the camera back is fully seated by successively squeezing all four corners between thumb and forefinger. When it is time to pull the dark slide I use my left hand to clamp the ground glass frame, the film holder, and the camera back tightly together so the forces of pulling the slide don't cause a tiny crack to open momentarily.

I use a lot of cheap film holders, some with rather "sticky" dark slides, but I no longer get light leaks since I changed my film holder routine.

[shadow images]

Had those on my zone vi/wista when I did not seat the back completely. I was trying to figure out why i had light leaks all of the sudden. Could hardly tell when it was off, it took me a little while to find it.

[nolindan]

Try the following:


Insert a film holder
Remove the lens board
Put a lightbulb inside the the camera via the lensboard opening, or if your hand will fit use a small flashlight inside the camera
Examine the back of the camera for light leaks


Do this before attempting any fixes - you want to maximize your probability of finding the problem area.

[Gem Singer]

Examining the photos of the back of your camera. The middle picture shows the groove in which accepts the tongue of the film holder.

It appears that the groove is not placed in the proper position. It seems to be cut too close to the film frame.

Could be a manufacturing defect. Perhaps it's just a distortion of the photograph.

However, it's worth looking into as the source of your problem.

[Bernard Kaye]

There is a white glue used by seamstresses that is vey tacky, it holds hems in place even when just spread but permits movement and washes off with warm water before it finally sets, is more tacky when cold, less tacky when warm; trade names as "Twice As Tacky," "Tacky" Glue, etc.
You can "glue" black hard or felty paper to your camera so it sits still, insert film holder,take picture, remove film holder, then peel off black paper and wipe-gently wash glue off camera leaving no trace if you work reasonably fast. If black paper is to be permanently glued to camera, it will be after a few hours or overnight..
Every house, every man needs a good woman's sense.
Bernie

[Gem Singer]

Hey Bernie,

The purpose of doing what you describe is????

[spacegoose]

I'll take a guess, Maybe the wood frame is warped a little? Perhaps you can try some black felt on either the frame or holder particularly at top right (or where ever the lower left in your pictures corresponds). Some nice shots by the way.

[Ivan J. Eberle]

You might easily screw up your focusing registration with the ground glass if you install felt in the film holder gate, while trying to cure a light leak.

[Rhemz]

You might easily screw up your focusing registration with the ground glass if you install felt in the film holder gate, while trying to cure a light leak.

Would I? If felt were affixed like so, wouldn't the ground glass be held back the same amount as a film holder?
http://www.be-logic.org/uploaded/1_felt.jpg




Thanks for the suggestions so far guys, I've examined the inside of the camera with a flashlight and found a few reflective strips of glossy wood and since painted over them with some matte dark-gray paint. I've also taken a few shots following Maris' advice of holding the film holder firmly in place while removing the dark slide to prevent any accidental movement (something I never paid very close attention to before). I will try affixing the felt in some non-permanent way and taking another few exposures this weekend to see if the problem was me, or in fact a camera leak.

[Bernard Kaye]

[QUOTE=Gem Singer;506420]Hey Bernie,

The purpose of doing what you describe is????

[/QUOTE

Thickness of black paper where you think light leak might be takes up warping of wood in camera back or film holder so film holder is firmly against back to block light leak if warping is what it is.

If leaving black paper on permanently to block light, it may put film out of register: if warping is on film holder, need a new film holder; if warping is on camera back, need a wood worker. Try it with more than one film holder.

Place film holders and camera back separately on absolutely flat (black heavy glass?) surface with light source shining from their other side to you to see if light comes to you from underneath holder or back. (see if they rock, light at ends; see if they bow, light more to center).

Wood warps.

Bernie

[Rhemz]

I'd like to thank everyone that helped -- the issue is resolved! It turned out it was that thin unpainted strip that I mentioned in the original post. I painted over it with some matte black paint & my leak cleared right up. Here are my first two successful LF exposures ever.

http://farm3.static.flickr.com/2423/3973516474_d2c387b790_o.jpg


http://farm3.static.flickr.com/2482/3973516564_793595cdda_o.jpg


I am so glad to have resolved this, and I can't wait to get back out there and spend some more time with the view camera.

Thanks again guys :)

[Bill_1856]

I don't know exactly how, but the fact that the light leak looks so different between your horizontal and vertical images makes me think that the removable back frame (the part you've shown in your pictures) isn't seating properly into the rear of the camera body itself.

[Bill_1856]

Guess I should have read the whole post before inserting my foot into my mouth and making a suggestion. (I didn't notice there were three pages of posts).

[al olson]

I'm not sure, Russ, that this has solved your problem. I agree with Louie and Maris that it appears that you are pulling the holder away from the back when you remove the dark slide.

When the holder is pulled slightly away from the back, the light leaking in from the side throws a shadow caused by the holder frame blocking the light near the edges. All three of your examples show this type of shadow near the edges. Further, your third image shows the greatest exposure near the dark slide end suggesting that this end of the holder was pulled away from the back.

I would suggest following Maris' procedures as a precaution to prevent this from happening.

[Photojeep]

It seems the issue has been resolved; whether by your darkening the shiny strip or being more careful with darkslide removal.

One thing I did notice was how you displayed your camera back. In the second photo, you have the ground glass standing perpendicular to the frame and I can't help but wonder how much stress is being placed on the springs. Perhaps they are a bit loose?

As I said above, you seem to have resolved your issue so have fun with your camera. (I would just not open the back quite so far any more...)

Best,
Photojeep

[don barnes]

Rhemz, I am new to the forum and you have probably already solved your light leak, but you may want to consider the film holders or your loading technique. I was taught to never let the full sun or other light hit the holder, especially the dark slide slot, any more than you have to. I try to shade my holder going from the bag to the camera under the dark cloth. I keep my film holders in insulated nylon 6 pack coolers for temp and light control. They are just right for 4x5 holders.

[Rhemz]

I'm not sure, Russ, that this has solved your problem. I agree with Louie and Maris that it appears that you are pulling the holder away from the back when you remove the dark slide.




You are quite right. Since reading Maris' post, I have been paying much closer attention when removing the dark slide. I painted the lip before taking the next set of exposures, so there's just as good a chance that did the trick.