long exposure light leak?

[MattKHardy]

Hi,

Been trying some long exposure photography in the mornings. Exposure time 5 minutes, 2-stop centre filter, polariser and 3-stop hard grad.

Nearly every shot is showing some sort of light leak coming from the top of the shot. The strongest band of light that leaks in from the top is in the same place every time.

198498

I have changed film holders but the result is the same.

Could this be due to stacking the polariser and grad? Could it be a leak from somewhere else?

Many thanks for any help!

[wager123]

check your view finder is covered

[wager123]

sorry cover the top of your film holder with your dark cloth

[MattKHardy]

sorry cover the top of your film holder with your dark cloth

Many thanks for your advice. Shall try placing the dark cloth over the holder, bellows and front standard.

It's such a pain as everything else is working well. I changed to using ID11 at stock, and agitating once a minute which reduced the grain.

[Paul Ron]

the top of that photo is actually the bottom of your film holder or camera. its inverted.

[MattKHardy]

the top of that photo is actually the bottom of your film holder or camera. its inverted.

So light maybe leaking from the bottom where the film-holder meets the standard :(

Is there any cure for this (apart from a new rear standard)?

[Louis Pacilla]

I would take your camera with a holder inserted in the spring back in a dark room put a bright flashlight inside the bellows and sit for 5-10 min until your eyes adjust & see if you get a hint of light making it's way out anywhere camera bellows,spring back.
You will also want to make sure you have no leaks in the holder/holders so do a paper test in your holders by putting a piece of RC paper in each side of the holder put them in strong light for a few hours then develop in Dektol or like paper developer and see if your troubles there. I doubt this but worth checking.

[Bruce Watson]

Nearly every shot is showing some sort of light leak coming from the top of the shot. The strongest band of light that leaks in from the top is in the same place every time.

If it's consistent across film holders, it's the camera and not the film holders. Most likely the springs that pull the back toward the camera body to "squeeze" the film holder aren't doing the job like they should. Easy enough to check. When you insert the film holder (before you pull the dark slide) use your hand to squeeze the "package" together -- that is, squeeze the camera body, film holder, and ground glass frame together, especially across the bottom where the light leak is. You can even tape (opaque) across the bottom of the camera (where your light leak is coming from) if you want. If that doesn't make it go away, the leak is farther forward. Maybe where the bellows attaches to the back.

The other thing to consider is whether the film holder is seating properly. Early in my LF learning curve I missed some good shots because I got in a hurry and didn't seat the film holder properly. Learned that lesson and hundreds more besides. LF photography is more exacting than I thought when I started out.

[ic-racer]

Some view of the negative might be helpful so one does not have to guess. Otherwise, guessing most people would insert the film holder from the top when making this shot, so that puts the light leak at the film notch side, yes? Do you open the film bags at the notch side? Maybe the bag is not sealed to light after opening? Do you process in some kind of tank with the film notches up? Maybe to tank top leaks light. Or check light leaks on the attachment of the bellows and film back on the bottom of the camera.

[Doremus Scudder]

Uhhh, film notches can go on either side of the film holder... just depends on how you like to load your film. Many people load filmholders with the notches up. My notches are always at the bottom (flap-side) of the holder so they have less tendency to impinge on the image area and so I can check to make sure the emulsion side is up just before closing the flap and inserting the dark slide.

I concur that the leak may be due to a misfit between either the camera back and holder or the camera back itself, but don't rule out leaks from the top of the back/holder area either, since that is where the light comes from... Do check the fit of both back and holder, but don't discount a small bellows leak just forward of the rear standard on the top of the bellows or where the bellows attaches to the camera.

Light traps in film holders aren't designed to be left open for minutes at a time either. Using the dark cloth over the whole camera for long exposures is a good idea if the wind allows. If not, you can do what I have: build a small cover out of old film boxes (they're black) that slips over the top of the filmholder when the slide is pulled.

Best,

Doremus

[Paul Ron]

you can put the light into the lens board hole. in a darkened room, inspect the entire camera with the bellows extended to check everything for the slightest leaks. be sure to put a film holder in with the dark slide removed as well.

this is the best way to find light leaks.



I would take your camera with a holder inserted in the spring back in a dark room put a bright flashlight inside the bellows and sit for 5-10 min until your eyes adjust & see if you get a hint of light making it's way out anywhere camera bellows,spring back.
You will also want to make sure you have no leaks in the holder/holders so do a paper test in your holders by putting a piece of RC paper in each side of the holder put them in strong light for a few hours then develop in Dektol or like paper developer and see if your troubles there. I doubt this but worth checking.

[MattKHardy]

Some view of the negative might be helpful so one does not have to guess. Otherwise, guessing most people would insert the film holder from the top when making this shot, so that puts the light leak at the film notch side, yes? Do you open the film bags at the notch side? Maybe the bag is not sealed to light after opening? Do you process in some kind of tank with the film notches up? Maybe to tank top leaks light. Or check light leaks on the attachment of the bellows and film back on the bottom of the camera.

Thanks for your time. Here is a shot of the negative

198504

[MattKHardy]

Uhhh, film notches can go on either side of the film holder... just depends on how you like to load your film. Many people load filmholders with the notches up. My notches are always at the bottom (flap-side) of the holder so they have less tendency to impinge on the image area and so I can check to make sure the emulsion side is up just before closing the flap and inserting the dark slide.

I concur that the leak may be due to a misfit between either the camera back and holder or the camera back itself, but don't rule out leaks from the top of the back/holder area either, since that is where the light comes from... Do check the fit of both back and holder, but don't discount a small bellows leak just forward of the rear standard on the top of the bellows or where the bellows attaches to the camera.

Light traps in film holders aren't designed to be left open for minutes at a time either. Using the dark cloth over the whole camera for long exposures is a good idea if the wind allows. If not, you can do what I have: build a small cover out of old film boxes (they're black) that slips over the top of the filmholder when the slide is pulled.

Best,

Doremus

Hi, thanks for your help!

I load my film with the notch flap side too.

I shall try covering the whole camera tomorrow morning with the dark cloth.

[MattKHardy]

Uhhh, film notches can go on either side of the film holder... just depends on how you like to load your film. Many people load filmholders with the notches up. My notches are always at the bottom (flap-side) of the holder so they have less tendency to impinge on the image area and so I can check to make sure the emulsion side is up just before closing the flap and inserting the dark slide.

I concur that the leak may be due to a misfit between either the camera back and holder or the camera back itself, but don't rule out leaks from the top of the back/holder area either, since that is where the light comes from... Do check the fit of both back and holder, but don't discount a small bellows leak just forward of the rear standard on the top of the bellows or where the bellows attaches to the camera.

Light traps in film holders aren't designed to be left open for minutes at a time either. Using the dark cloth over the whole camera for long exposures is a good idea if the wind allows. If not, you can do what I have: build a small cover out of old film boxes (they're black) that slips over the top of the filmholder when the slide is pulled.

Best,

Doremus

OK took the photo again. Put the dark cloth over the front standard, bellows and rear standard.

198525

Light leak still in the same place :(

Shall start taping all the joints...

[Paul Ron]

do the light test from the front as well as from the rear. it can be the lensboard not seating too.

[scheinfluger_77]

How sure are we this is not a lens artifact?

[MattKHardy]

How sure are we this is not a lens artifact?

Maybe due to stacking the centre-filter, polariser and grad?

Shall try again with them removed...

[ic-racer]

Thanks for your time. Here is a shot of the negative

198504
I have only ever used ND filters either behind the lens or screw-on the front. I have never seen a slide-in filter holder that seals light effectively, so it looks like that is the issue; light leak between the nd filters and the lens.

[MattKHardy]

How sure are we this is not a lens artifact?

Hi,

Pretty sure its not a lens artifact. I repeated the photo today with the same setup: centre-filter, grad filter, polarizer, f22, five minute exposure on Delta 100.

This time in landscape orientation:

198550

Rotating the Graflok back to landscape orientation seems to stop the light leak. This must point to the seating of the Graflok?

[Doremus Scudder]

... This must point to the seating of the Graflok?

That's where I'd look. From the look of the negative, the light-strike is definitely happening in-camera.

BTW, taping flaps on filmholders does nothing but hold the flap... The flaps have baffles, and as long as the flap is closed, no light makes it in from the bottom. The tape is just a hinge (and keeps the flaps from falling off :) ).

Keep at it; you'll find the problem eventually.

Best,

Doremus

[Paul Ron]

and how did the light test go?



.

[MattKHardy]

and how did the light test go?



.

Took the camera into a darkened room, removed the front lens panel and pointed a bright LED torch directly underneath the Graflok (where it joins to the rear standard). Pitch-black, couldn't see any light leaking through... :confused:

TBH I cant see how any light could get through, the Graflok and standard are chunky pieces of metal, could they wear/bend/warp?

[Paul Ron]

the leak doesnt have to be that large. it only has to pass a joining surface and can be as small as a pin prick. it takes very careful inspection of every meeting surface and dont forget to test the bellows.

it doesnt have to be warpage or deformaties. it may be a weak spring or mismatched joint due to dirt or even a lose screw. worn seals, depending on your camera, are always suspect. is this a wood camera?

did you also try the light from the rear to see if the lensboard is leaking?

if the problem happens with other film holders, the leak is from the camera.

just be patient n do the test again looking closely at everything, not just point the light at a single component. if you can, use a regular house led bulb, a small focused beam is too directional.

btw,... the light source goes inside the camera.

[Louis Pacilla]

Go in darkroom take lens board off PUT FLASH LIGHT INSIDE the CAMERA put lens board back on. sit 10-20 minutes to let eyes fully adjust to darkness. FLASH LIGHT GOES INSIDE OPENED/set up camera with a holder in spring back & pull slide out of holder for good measure. Now study camera from all angles and see if any pin holes of light can be detected.

[Doremus Scudder]

Louis makes a good point: be sure to check for leaks with a filmholder in the camera. Check at all orientations of the back too.

Doremus

[Tracy Storer]

is it possible there is something shiny INSIDE the camera ? I have seen this more than once where there's a problem surface, and it'll show only with the back oriented one way.

You could tell us what kind of camera it is, how old, etc.

[MattKHardy]

is it possible there is something shiny INSIDE the camera ? I have seen this more than once where there's a problem surface, and it'll show only with the back oriented one way.

You could tell us what kind of camera it is, how old, etc.

Hi Tracy,

Its a Sinar F1 with wide-angle bag-bellows. The bag-bellows are in good condition, hardly used. However the rear standard looks pretty old.

Here is another shot with a different lens (Schneider 150mm) and lens-board. The contrast is cranked up to better show the leak.

198812

The rear standard has a soft gasket inside the groove where the graflok sits (along the bottom edge). This picture seems to point to that gasket (it does look worn and squashed). When the graflok is in landscape orientation that bottom edge is covered by a ridge in the graflok. Only two sides have that ridge. In portrait orientation there is no ridge to block the leak coming from the bottom edge.

198813

Is it possible to scrape out that gasket and replace with a DIY one?

[Vaughn]

The rear standard has a soft gasket inside the groove where the graflok sits (along the bottom edge). This picture seems to point to that gasket (it does look worn and squashed). When the graflok is in landscape orientation that bottom edge is covered by a ridge in the graflok. Only two sides have that ridge. In portrait orientation there is no ridge to block the leak coming from the bottom edge.

That is something the flashlight test would easily show if done as suggested by Louis.

[MattKHardy]

Go in darkroom take lens board off PUT FLASH LIGHT INSIDE the CAMERA put lens board back on. sit 10-20 minutes to let eyes fully adjust to darkness. FLASH LIGHT GOES INSIDE OPENED/set up camera with a holder in spring back & pull slide out of holder for good measure. Now study camera from all angles and see if any pin holes of light can be detected.

Hi Louis,

Finally got around to trying this again after the Christmas holidays.

There are tiny leaks in both bottom corners of the rear standard, where the Graflok attaches to the back of the rear-standard, and where bellows attaches to the front of the rear-standard :(

Looking at the light-pattern of the leak I bet there are other leaks along the bottom edge that I cant detect.

I have some sticky felt gasket I can try cutting to size and putting in the corners...

[Louis Pacilla]

Hi Louis,

Finally got around to trying this again after the Christmas holidays.

There are tiny leaks in both bottom corners of the rear standard, where the Graflok attaches to the back of the rear-standard, and where bellows attaches to the front of the rear-standard :(

Looking at the light-pattern of the leak I bet there are other leaks along the bottom edge that I cant detect.

I have some sticky felt gasket I can try cutting to size and putting in the corners...

Great! Once you've located the leak/leaks the next step (your doing) patch the leaks do another light leak test to make sure you've corrected the leak. Now try the camera out in field and see if the leak is gone.

Your on the road to a success!

[Paul Ron]

you can replace the old foam seals with new. its very easy, just scrape n clean it well. pick the thickness you need and cut strips. the new foam is self stick.

you can get a variety kit of foam sheets in several thicknesses here....

https://www.micro-tools.com/products/lb-kit

.

[C. D. Keth]

If you find the inside of your camera has any surfaces that are shiny or have had black paint wear off, you can get adhesive black flocking material from online stores that cater to people who make their own telescopes. $20 will pretty much buy a lifetime's worth.

[MattKHardy]

OK, replaced the seals at the bottom and took a picture. Stupidly I tried adding a yellow filter (Lee B&W polyester filter set, xmas present) and this seems to have introduced new problems (contrast added to highlight issues):

199007

Are the rings are due to the filter?! :mad:. However the original leak issue still seems to be in the same place, but looks different? Or is it streaky clouds?

Tempted to bin the filters and the rear standard as its soaking up too much time and film...

[MattKHardy]

OK, replaced the seals at the bottom and took a picture. Stupidly I tried adding a yellow filter (Lee B&W polyester filter set, xmas present) and this seems to have introduced new problems (contrast added to highlight issues):

199007

Are the rings are due to the filter?! :mad:. However the original leak issue still seems to be in the same place, but looks different? Or is it streaky clouds?

Tempted to bin the filters and the rear standard as its soaking up too much time and film...

Rings issue reproduced with a digital camera. Happens with the yellow filter on top of a linear polarizer...

[Andrew Tymon]

Matt, you said this doesn't happen when the back is in landscape orientation correct? I'm not familiar with how this back switches between landscape and portrait mode, do you have to remove and manually turn it or does it rotate. Seems something is not seating right when in portrait mode. Maybe you could use black electrical tape to seal the joint between the back and rear standard to see if that eliminates the issue, all be it temporarily.

[MattKHardy]

Matt, you said this doesn't happen when the back is in landscape orientation correct? I'm not familiar with how this back switches between landscape and portrait mode, do you have to remove and manually turn it or does it rotate. Seems something is not seating right when in portrait mode. Maybe you could use black electrical tape to seal the joint between the back and rear standard to see if that eliminates the issue, all be it temporarily.

Hi Andrew,

Thanks for the advice. It has to be removed and manually rotated.

In landscape mode there is a ridge that runs across the bottom edge and sits over the join.

[MattKHardy]

If you find the inside of your camera has any surfaces that are shiny or have had black paint wear off, you can get adhesive black flocking material from online stores that cater to people who make their own telescopes. $20 will pretty much buy a lifetime's worth.

Spent a good 30 minutes today shining a torch around around every inch of the standards and bellows and I still couldn't find any more light leaks. So I loaded a sheet of film, took the slide out, and left the camera outside in daylight for five minutes. This is the developed film:

199105

Its solid/black/blank. So surely the light leaks are now fixed? If they weren't, they would appear as a light streak in the same place?

Internal reflections might still be an issue?

[Andrew Tymon]

If the shutter was closed the film should be clear as no light should have entered the bellows. It may be my monitor but I see a line of density about two thirds of the way up extending from the left edge.

[MattKHardy]

If the shutter was closed the film should be clear as no light should have entered the bellows. It may be my monitor but I see a line of density about two thirds of the way up extending from the left edge.

Shutter was closed.

Yeah can see the line as well. Maybe it's developement anomalies? As it's darker its not a leak?

[Andrew Tymon]

Matt is the film clear? Or is this an inverted image of the neg?

[MattKHardy]

Matt is the film clear? Or is this an inverted image of the neg?

The film was clear after dev/fix. The negative is transparent and slightly pink (delta 100).

The image I posted is a scan from epson software.

[Andrew Tymon]

Maybe you got them all then if the film was clear.

[MattKHardy]

The band at the top of the photos was caused by the fins on the Paterson Orbital developer :mad: They only affected areas of high density (the sky). In landscape orientation the area of sky was rotated to the RHS of the tray of out of the path of the fin. The fins have now been sawn off...

199313

Thanks for everyones continued encouragement to find/fix any light leaks and reflections. This allowed me to address additional problems (found/filled two light leaks, cleaned/painted the graflok) and my camera is now producing much better photos :)

Off down to the river to try that photo again!

[Andrew Tymon]

Yay! :)