Dust on my negs at time of exposure?

After shooting for a couple of months with my shiny new Intrepid 4x5, I started noticing a lot of my photos had little black squiggles all over the prints. Looked like dust on the negative. These same ones show up in the scans, even if I do a really good job blowing off the negs with compressed air and brushing with an anti-static brush before placing in the negative carrier for the enlarger or scanner.

After examining a few negs carefully with a loupe, I saw that the dust marks were actually exposed into the film, which explains why the dust shows up as black instead of white in the prints/scans, and why I can't seem to get rid of them.

So... how exactly does one go about getting dust off of a negative while it's loaded in the camera, before exposing? I can't think of a method to blow the negative off while it's in a film holder without inadvertently exposing it to light. Kinda frustrating, it has all but ruined a couple of photos that I was otherwise very happy with. I use my film holders enough that I can't imagine how they have enough dust on them to actually get on the negative when I pull the darkslide out, so I'm at a loss to explain where this is coming from.

I have ruled out scratches in the emulsion (which is what I initially suspected). The marks do not appear on all of my negs, only some. I am using a Beseler Color 8x10 tube to develop the films by rotary agitation on a motorized base, and only load two negatives into the tube at one time max (one on each side, so no overlap or contact with corners, etc.). Furthermore, during a recent shoot I had one side of a film holder loaded incorrectly, which stopped me from putting the darkslide back in after exposing the sheet. I had to pull out the film holder and fry the negative. When I pulled it out of the camera back and saw that it had jumped the rail in the film holder, I also noted that it had what looked like tiny black hairs scattered over part of it, exactly the size and shape of the stuff I had been seeing in my prints and scans.

(Speculation here) Might there be some sort of felt/fabric dark slide light seal material disintegrating and getting scattered over the film surface? I don't shoot much 4x5, but when I started using some holders that had been dormant for 20 years, I vacuumed the bejeebers out of them and also cleaned up the dark slides with an automotive cleaner/polish. So far, in my limited use, I've not seen a problem, but with large objects being swapped in and out, the possibility of unwanted material appearing is presumably always there.

Do you live in a dry or humid climate? I live in a dry one so here goes:

No matter what steps I take, anti-static bag storage, cleaning out the holders, inside of the camera, etc. I always lose about 30-50% of my shots to pre-exposure dust. So I "dust bracket" on really important shots which means I shoot 6 sheets instead of two.

You will have countless people come on here and say you are doing something wrong because they never have issues with dust but in the real world, this is the number one reason large format takes a firm back seat to medium format for me, the risk and reality of losing brilliant photographs to the nearly impossible to deal with black marks left on prints by pre-exposure dust.

The struggle is real and even LF masters like John Sexton say that this is the number one issue they have with shooting sheet film, especially now that readyloads are long gone. You are going to have to go to great lengths to avoid it and then go through more film than you might want to ensure you have a printable negative...it is that big of an issue.

BHuij said:

After shooting for a couple of months with my shiny new Intrepid 4x5, I started noticing a lot of my photos had little black squiggles all over the prints. Looked like dust on the negative. These same ones show up in the scans, even if I do a really good job blowing off the negs with compressed air and brushing with an anti-static brush before placing in the negative carrier for the enlarger or scanner.

After examining a few negs carefully with a loupe, I saw that the dust marks were actually exposed into the film, which explains why the dust shows up as black instead of white in the prints/scans, and why I can't seem to get rid of them.

So... how exactly does one go about getting dust off of a negative while it's loaded in the camera, before exposing? I can't think of a method to blow the negative off while it's in a film holder without inadvertently exposing it to light. Kinda frustrating, it has all but ruined a couple of photos that I was otherwise very happy with. I use my film holders enough that I can't imagine how they have enough dust on them to actually get on the negative when I pull the darkslide out, so I'm at a loss to explain where this is coming from.

I have ruled out scratches in the emulsion (which is what I initially suspected). The marks do not appear on all of my negs, only some. I am using a Beseler Color 8x10 tube to develop the films by rotary agitation on a motorized base, and only load two negatives into the tube at one time max (one on each side, so no overlap or contact with corners, etc.). Furthermore, during a recent shoot I had one side of a film holder loaded incorrectly, which stopped me from putting the darkslide back in after exposing the sheet. I had to pull out the film holder and fry the negative. When I pulled it out of the camera back and saw that it had jumped the rail in the film holder, I also noted that it had what looked like tiny black hairs scattered over part of it, exactly the size and shape of the stuff I had been seeing in my prints and scans.

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I'ts a common problem? All you can do is knocking the holders on a flat surface lightly and vacuum them before loading. It ink,it's fair to asume that fresh fil is sold dust free.

That's... disheartening. Just did a bunch of reading up, I hadn't realized this was such a widespread problem.

I did find some good suggestions both to prevent the dust and to spot correct the film base side of the actual negative with a pencil if there is dust exposed on it. Have some things to try now. Thanks all!

BHuij said:

That's... disheartening. Just did a bunch of reading up, I hadn't realized this was such a widespread problem.

I did find some good suggestions both to prevent the dust and to spot correct the film base side of the actual negative with a pencil if there is dust exposed on it. Have some things to try now. Thanks all!

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It is a bit disheartening indeed. I think a lot of the dismissal of it as a real issue stems from just how many people use hybrid means to arrive at a print in which one can just get rid of it at the software stage. For those of us who only darkroom print, it can be maddening.

I take such issue with it that I am actually building a dedicated sheet film loading area in my new darkroom that will be like a clean room complete with hepa filtration, etc. I also tap the holder on a tripod leg a couple times right before I insert it as a last step before making an exposure.

Keep reading up, I can assure you that it will improve once you become one with the drudgery of it all but it is well worth it since the only thing worse than increasing your per scene cost in using more film is coming home with no useable images of an otherwise incredible photograph due to dust.

Don't lose heart. Keeping things clean for loading isn't as hard as you may think.

Your film is clean and dust free inside the box. You can and should ensure that your holders are clean and dust free before loading the film into them. The enemy, however, is airborne dust. You need a nice dust-free environment to load your holders in. I have a darkroom with filters in the U.S., but in Europe use a lightproofed bathroom. My wife loves me on filmholder-loading day because I clean the bathroom to NASA cleanroom specs before loading.

My routine: I take the film out of the fridge to warm up to room temp. While that's happening, I start in on the bathroom. Rugs and mats come out and get shaken outside and don't go back in again till I'm done loading. Then I wipe down the walls and counter tops, etc., etc. with a lint free cloth and window cleaner. When all the upper surfaces are clean, the bathroom then gets a good vacuuming. I make sure to keep the vacuum outside the bathroom as much as possible when doing this to keep the exhaust air from recirculating into the room. After vacuuming I go over walls, countertops and floors again with a fresh, slightly damp lint-free cloth. I then run the hot water for a few minutes to settle the dust. After that, I try not to disturb anything till the holders are loaded.

Before loading, I vacuum the holders in the bathroom. I have an upholstery attachment for the vacuum cleaner that is reserved just for filmholders. I pay special attention to the light trap, running the slide through a couple of times while vacuuming. The body of the vacuum stays outside the bathroom during this process. I stack the clean holders with darkslides closed on the counter and cover them with a new ZipLoc bag to keep airborne dust from settling on them. When the holders are all clean, I make sure I'm wearing lint-free clothes, wash my hands up to my elbows like a surgeon getting ready for an operation and don a shower cap I've appropriated from a hotel room somewhere. When I wore a beard, I made sure it was clean and combed out (in another room) before loading.

Then, it's get the film and lights out. When loading, I keep my body, especially my head away from directly over the loading area. I open the film box and take the entire stack of film from its envelope and place it emulsion-side-down on the counter. Any airborne dust now will land the back of the film and the outside of the darkslide. During the actual loading I try to minimize the time the film surface is exposed. I grab a holder, pull the darkslide out halfway (or a little less) then quickly grab a sheet of film which I turn up vertically and tap once or twice on the countertop to dislodge any dust that might be there. It then gets flipped the rest of the way and slid into the filmholder. I like notches on the flap end of the holder so I can confirm correct position by feel at the same time I check to make sure the film is under the guide rails by lifting up the corners slightly. Then the slide is reinserted and the holder flipped and the process repeated.

At the end of loading, each holder goes into its own ZipLoc or similar plastic bag. These live on a shelf, in my filmholder cooler or in my camera kit till needed.

Before going out to photograph, I make sure my camera is clean inside and out. Before an outing I'll extend the bellows, remove back and lensboard and lightly blow dust from the interior of the camera till it's clean. Finally, just before shooting, I'll clean off the outside of the filmholder bag before opening, and then check the filmholder itself for dust (somehow, there always is some). I'll blow off the dust or use a brush I carry to brush stubborn specs off the darkslide before inserting it into the camera. Then I remove the darkslide slowly to keep static from building up and attracting any dust that is inside the camera and make the shot as quickly as practical to keep the time the film is exposed to airborne dust before the exposure to a minimum. After the exposure, who cares... the dust will come off during processing.

Finally, I've mastered the art of retouching negatives and etching prints to remove the inevitable few dust spots on the negatives that still somehow manage to crop up.

Well, that sounds more complicated than it really is if you develop the habits. Once your filmholders and cameras are really clean and you keep them that way, dust becomes much less of a problem.

Hope this helps,

Doremus

You need to find out the source of these tiny black hairs. I would start by looking inside the bellows. How old are your film holders? I had a couple of old, used 8x10 holders with light traps that were decaying, leaving fuzzies on the film.

Andrew also has the advantage that he lives on the We(s)t Coast, and also travels and photographs in Japan. I don't know what happens when he visits the Okanagan or Saskatchewan.
Slightly more seriously, higher relative humidity definitely helps with dust.

I live in the second driest state in the union, so no humidity to help things along for me.

Between my own reading and all your replies, I feel very much better equipped to prevent this problem in the future. Looking forward to giving my film holders some love with the vaccuum tonight.

I've never had a problem with dust, but I load my film holders inside a tent style dark bag, so maybe that has something to do with it. Before I use the bag, I grab the frame and bellow it a few times pushing air in and out, with the opening facing down. I sometimes do get dust spots on my negs of course. Best solution to that if you are making prints is to get yourself a super fine Sakura pen, a light box, and a steady hand. Put a dot on the non emulsion side of the neg. You could try Spot Tone too, but I prefer just to get it over with and make the area white. It is a lot easier to spot a print than knife it.

Hope that helps.

Matt is correct. High humidity is a large format film loader's friend. I never had serious dust issues until I started photographing in my home province of Saskatchewan. Always took great care in wiping down film tent and holders. Tac rags from hardware stores are the best. Static electricity is an issue there too. One must pull that slide out sloooowly! Those static cling sheets help. I keep one inside a plastic Ziploc along with the film holder.
Japan is extremely humid in the summer and hands can drip with sweat inside that changing tent. I've had film stick together from my sweat!

Heading up to Kamloops next week. Another very dry and dusty place. Gotta get cleaning those holders!

Compressed air does a better job or removing dust than vacuuming. Remove the lens board and back from the camera, extend the bellows then blow out the inside of the bellows on ocassion.

I'm not always great at cleaning my film holders every single time I reload, but they do get cleaned every few sheets. The only times (so far, and knock on wood) I've had dust on film before shooting was when I was using a changing tent to load the holders. It is doable to keep the dust down, but a little effort is required.

Just put in the negative and give a big blow as you slide the dark slide in. That will help for 99%.

In light of the replies above, you can easily see that compared to medium format which can also have dust issues if you don't keep your cameras and backs clean, one could possibly have to go to what I consider to be extraordinary lengths to get printable negatives.

Since I don't do this as a hobby, I have to produce when out in the field so I always dust bracket, have done as many as 10 sheets on a single scene if I can not afford to lose the shot.

Using 6x12 roll film backs also keeps me in the production zone and for obvious reasons, is far less prone to dust.

So I can not express enough to the OP or anyone in the future who might read this, if you have the shot of a lifetime in front of you and you have time, shoot at *least* half a dozen sheets just to mitigate the possibility of dust ruining a shot. Just because it does not happen to other people on here does not mean it won't happen to you.

And beware of humidity, very bad. It gives rust, fungus, fingerprints on the negs, not good. Keep your gear dry.

Ai Print said:

No matter what steps I take, anti-static bag storage, cleaning out the holders, inside of the camera, etc. I always lose about 30-50% of my shots to pre-exposure dust.

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Holy cow! I've never worked with 4x5 in really low humidity, but if I were losing that much to dust I'd be on a major dust study and eradication program.

I've been involved with major efforts to control dust on the other end of the business - in lab work. The same principles apply, I'm sure. If humidity is really low, static charges on film take a long time to bleed off, certainly longer than you'll want to spend loading film holders. And is somewhat fruitless to attempt to blow off tiny dust particles when static has a grip on them - they're easy to move around, but tough to dislodge. And simply separating sheets of film from the box will tend to generate some static charge.

I'm not gonna advise too much unless specifically asked, but I'd be sacrificing a few sheets of film, pulling open the dark slides in a clean room for careful inspection with hard lights and strong magnification. (You can use these same sheets, over and over in your study). Then, when I find dust, examine to guess what it might be. Maybe pull and replace the dark slide a dozen times or so to see if dust is internal to the film holder system. I wouldn't automatically assume the film is pristine inside the box, either.

If someone wanted to make a clean film holder-loading booth, I'd suggest to get the area humidified into the 40-50% RH level (do NOT let one of those little plug-in units that you fill with water anywhere near your film, at least while it's running). If you do this, at least your film won't be a dust magnet, and you'll be able to blow the major dust off. You don't need to go so far as HEPA filters, which will easily stop cigarette smoke, but it won't hurt. Anyway, if you make a small filter "wall," say 2x2 feet, and have it blow clean air towards you, you'll be able to load film holders without your own dust getting into the act. If you put up a couple of short side walls, even a little foamcore, it'll keep room air from being pulled into the film handling area. If you wanted to, and had good, clean compressed air, you could even give the film a short blast in the open film holder.

Something that a lot of people might not recognize are film skivings - little pigtail-shaped bits of emulsion, typically shaved from the edges. You might even have a couple of film holders that do this to the film as you load it. It's possible, too, depending on how well the film was cut, that the cut edges might have partially sheared bits of emulsion hanging on.

Anyway, this is my idea of "not advising too much." But I really don't think you have to live with ~1/3 of your sheet film picking up "noticeable" dust. I could be wrong about this, but I'm doubtful; there won't be too many people who have worked with the dust-on-film issue as I have.

Dust on sheet film is more evil than chance would suggest. It settles preferentially on areas that are going to be skies or faces. Eliminate these two pieces of subject matter and the dust problem virtually disappears.

I found early in my 4x5 field work that using a changing bag to reload holders is asking for dust problems. Turning the bag inside out occasionally and damp wiping its inside surface helped a bit. Then I switched to a reloading tent which helps keep it from touching the film/holders was a lot better. Also in cold dry climes, static electricity caused the holders to be a magnet for dust UNTIL I started wiping the darkslides with a product called Brillianize. I'd spray it on the darkslides then wipe off excess - that killed the static charge issue. I get that stuff from a local plastics store chain on the west coast (TAPplastics.com) but other sources likely have it as well. Works equally well on metals, too.

If dust is a problem, then use a changing bag for loading your film into the holders. Don't use the same changing bag for swapping out film in the field. Once a bag gets dust inside of it, it's really hard to make sterile again. It's a lot easier to control the level of dust in a tiny room like a changing bag than in an entire dark room. Also, be sure to thoroughly wash and dry your hands and arms before sticking them inside your changing bag, and don't ever open the changing bag for any longer than you have to. And when you store it, store in it in a gallon ziplock bag with the sleeves folded over to keep them from being exposed. It all sounds like a ton of work, but in reality, it's not too bad.

Also, as others have stated, be sure to clean your film holders between every use (if possible), and clean your camera's bellows often. I also store my film holders in gallon sized ziplock bags (usually in the fridge with film in them, ready to go), to help keep dust off. If you keep stuff clean to begin with and establish a routine, then cleaning them on a regular basis is quick and easy. It only takes me about 10 seconds to clean each film holder because they're not really ever dirty to begin with.

The thing with dust is it's a lot easier to keep out than it is to remove.

BHuij said:

I live in the second driest state in the union,.

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In one sense of the word "dry" isn't it the driest State in the Union?

pentaxuser

pentaxuser said:

In one sense of the word "dry" isn't it the driest State in the Union?

pentaxuser

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Hahaha that it is, my friend. And after having lived in Russia for two years, let me tell you how refreshing it is to live in such a dry state

Dust on negatives is for me the most difficult part of darkroom work (I live in a very dry climate). When I started out years ago I thought I was doing not too bad until I tried to print a very low-key negative -- 2/3 near-black background behind a front-lit figure. Just horrible.
After that I started taking all the precautions, Photo-Flo, drying in a dampish superclean surroundings, a blower, anti-static cloths, etc. etc. Now the result is usually OK.
Of course the greater the surface area of the negative the more careful you have to be! You don't get anything for nothing.
Looking at all the above it seems best to live somewhere with absolute average humidity.