There are two different problems that are called “pinholes” in negatives. They’re quite different from each other.
A true pinhole is caused by a small air bubble in the emulsion or a gap in the emulsion. After coating, when the emulsion had dried, it leaves a tiny circular area of no emulsion. Usually, the gelatin overcoat covers it. There’s no emulsion to expose in the spot, so the area stays clear after development. In the enlarger, the light pours through the clear spot with full force exposing a black spot on the paper.
The only true pinholes I’ve ever encountered happed with the Hungarian-made Fortepan 100 and 400 films. Pinholes occurred frequently. I have never seen a true pinhole in Kodak, Ilford, Agfa, Fuji, Konica, or 3M branded films.
The much more common “shadow pinhole” can happen in any camera, but is most often a problem in sheet film or glass plates. This happens in roll-film cameras very rarely when a particle—almost always from the interior of camera that isn’t routinely blown out with a squeeze bulb blower as part of regular maintenance. Particles can enter a camera anytime the body is open to the air: film changing, changing backs, changing lenses.
The turbulence of a reflex mirror snapping abruptly to the shooting position can create a cloud of particles that can stick to the emulsion. This is one of the reasons that many camera makers advise blowing out the camera as part of regular maintenance. Any such particle will block the projected image light from the lens and cast a shadow on the emulsion. When developed, the shadow is a clear spot on the negative. This is often referred to as a “pinhole” even though it’s quite different than a true pinhole.
Users of sheet film and glass plate cameras are particularly plagued with pinholes produced by the shadows of particles or even small fibers adhering to the emulsion at exposure because the film is handled unshielded in the darkroom during the loading of the holder.
Once formed, there are three ways to deal with pinholes of either type:
1. Use a pointed wooden toothpick to apply a tiny amount of opaque material to the top (base surface) of the negative to block the light from the pinhole. This is best done on a light table with strong magnifying eyeglasses or a loupe. The resulting white spot on the print is then spot dyed to match the surrounding area. I prefer to use red WATER-SOLUBLE poster paint because, if I do a poor job of placing the paint, I can wash the negative to remove the paint, dry it and try again. I think it’s a bad idea to place the opaque material on the emulsion side as the emulsion might get damaged. Obviously, if you use an indelible opaque material, you have only one chance to get it right. It’s much safer to use a water-soluble material so that you can wash it off and try again if the first try is unsuccessful. The size of the negative matters. The larger the negative, the easier it is to place opaque material onto the negative. 35mm negatives are too small for this to be practical (at least for me).
2. Make the print with the dark spot projected through the pinhole and use a photographic bleach applied with a toothpick to the black spot followed by washing. Afterwards, the bleached area will have to be spot dyed to match the surrounding area. Retouch Methods, the former maker of Spotone dyes used to make a 2-bottle spot bleaching kit called Spot-Off for bleaching black spots on prints. You can make your own with Farmer’s reducer.
3. On FIBER-BASED PAPER ONLY, use a curved-blade Exacto knife to gently scrape the emulsion just enough to remove the excess density of the black spot and then spot dye to match the surrounding area. There used to be specialized print-etching knives made specifically for this purpose, but the proper blade in the Exacto knife works reasonably well. Knifing the print will necessarily alter the surface. The surface can be made uniform by giving it several coats of light spray lacquer (the entire print gets coated, dull or gloss as you prefer). Knifing black spots is not practical on RC prints.
Of these three methods, #1 is usually the most practical, provided that the negative is large enough. Small negatives require method 2 or 3. In Ansel Adam’s book, The Print, a photo of one of Adams’ print finishers is shown knifing a tiny black spot in the light sky area of an otherwise perfect print. The accompanying text explains the process.
Last edited by Ian C; 12-06-2012 at 12:25 PM. Click to view previous post history.
I'd place a tiny piece of rolled up blu-tac on the paper and then spot.
How about tweezing a speck of lint onto the paper in the easel under red light.
I'd tried something similar (I called it a "mosquito") to dodge a clear outlined area, but the effect was disturbing. But for a speck, this might do the trick.
A quick, dirty, and permanent fix for an emulsion pinhole is to stab the emulsion with a dress-makers pin right on top of the pinhole. Yes! Push the pin in right down to the film base if necessary. The resulting concave dimple diverts enlarger light away from the defect and the black spot in the positive disappears...more or less. This technique was a favourite with the old press photographers who could not wait for red opaque or spotting dye to dry.
Photography, the word itself, invented and defined by its author Sir John.F.W.Herschel, 14 March 1839 at the Royal Society, Somerset House, London. Quote "...Photography or the application of the Chemical rays of light to the purpose of pictorial representation,..". unquote.
I think I'm not going to stab my film (thanks Maris for sharing this tip) but I will try method that were mentioned in this thread. I thought about putting a small ball bearing or something on print but it is so hard to see the dot under safety red light.
The "dot" is small enough to be difficult but large enough to be visible.
Thanks everybody for sharing your ideas.
Develop, stop, fix.... wait.... where's my film?
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I've used a red extra-fine Sharpie to mask the pinhole, but yours might be too small for that. I have used a product called spot pens to bleach the black spot on the print to white, and then spotone it. This worked fine, but have to go easy as the bleach spreads a bit.
I think I'll try that pin prick trick on a wasted negative, thanks.
How do I deal with a pin hole on neg?
On sheet film I often use a tiny piece of ruby lith tape to cover offending dust spots and then spot the print. The tape is easily removed if wanted.
There is a very high quality solution if you have a masking system. Basically what you can do is place a piece of film under your negative and expose it to white light under your enlarger. You expose/develop the target film in such a way as to end up with only your black pinhole dot on it. With the masking system the negative and your target film are easily exactly aligned and placed together in the neg carrier (possibly with some diffusion between the two to reduce any edge effects). You would then have a custom made pinhole dodger! You wouldn't have to alter your original neg and the result would be repeatable print to print. This works best on 120 film and larger.
Another approach would be to tape a piece of mylar, or some other opaque material that would take a pencil or pen, on top of your neg. On a light table, try to put a precise dodging dot on the mylar, then try to print through this sandwich. It would be tough to do well, but might at least lighten the dot and make it easier to deal with.
Let me know if any questions,
I can report the following so far.
Knifing the print does not work on this surface. (RC Pearl) I can scrape the dark spot off but it won't take spotall afterwards.
Placing a 'fly' on the spot under red light is impossible. I can't see!
I am not stabbing my film.
Under microscope, I tried to put a "dot" on the neg. Even the smallest spot is too big.
Try to use a needle. Ink won't stay on the very tip.
I don't have a registration system so that isn't workable for me.
I might have to reshoot this....
Develop, stop, fix.... wait.... where's my film?