Tips for keeping 35mm negatives dust and scratch freegreenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
Can you please give me tips to keep my 35mm negatives clean, and dust/scratch free during the processing, developing and printing stages. I take great care, but I still end up with scratchs and dust ususally - often this can be fixed by simply whipping the negative with lint-free lens tissues prior to print developing - but more than often it is hard to remove all scratchs. So any tips about any related processor for keeping clean negs would be greatly appreciated :)
-- Simon Fisher (firstname.lastname@example.org), March 24, 2000
My choice for removing tiny specks of dust is air. Wiping is always dangerous, as scratches may result, and scratches cannot really be removed. Before putting my negative in the enlarger, I visually inspect it using the kind of magnifying glasses watchmakers wear. Dust is best seen in grazing light. (This is hard to explain in plain text, a sketch would be easy.) To check for dust, hold the negative under your enlarger lens, its plane parallel to the optical axis of the lens. Light incidence is then almost parallel to the negative. When everything is dark around the negative save the light from the enlarger, any little speck of dust will be very bright against a dark background. To remove dust, use compressed air. I am very fond of my little blower ball. (I'd really appreciate hearing the proper name for this item from a native speaker. I couldn't find it in the dictionary. It is basically a hollow rubber ball with a nozzle). When I press this ball really hard, a nice hard air jet results, which blows away practically all dust. Dust sticking to the surface (for example because it got there while the film was still wet) must be removed using a soft cloth. Careful!
-- Thomas Wollstein (email@example.com), March 24, 2000.
Hi, I believe the classic brand of these blowers is the "Hurricane Blower". What most people use is a common drugstore "ear syringe", which usually comes in two sizes. I've used the large one for many years with good results. BTW, I've used soft paper towels as darkroom wipes for quite a while, but recently they seem to contain some very abrasive substance- don't use these for cleaning negatives, condensers, or anything else of value!
-- Conrad Hoffman (firstname.lastname@example.org), March 24, 2000.
Prevention is best. You might try hardener in your film fixer to help prevent scratches. After processing, soak your film in Photoflo for 30 seconds with agitation, then hang it up to dry in the most dust-free area you have for an hour or until it's fully dry, but no longer. Then cut it into strips and store in one of B&H's negative sheets. Leave the negatives in their sheet when making contact prints. Only take them out to put them in your negative carrier. Store the sheets in a box to keep dust from settling on them.
-- Brian Hinther (BrianH@sd314.k12.id.us), March 24, 2000.
I can't quite see why one should not hang the film for more than half an hour. When the film is dry, any dust settling on it will not stick to it so tightly that you couldn't blow it away. The film hanging in the vertical, dust is also not too likely to settle on it. Also, my films are seldom completely dry after half an hour, so they are still a bit sticky (great when they stick to something like the sheet) and soft (thus vulnerable). I always leave my film hanging over night. Then it is dry, and safe to handle.
-- Thomas Wollstein (email@example.com), March 27, 2000.
Try handling the negatives as little as possible, especially pushing or pulling them through plastic sleeves; fine base scratches may result. And NEVER pull a negative strip through a film gate, no matter who says you can; you will scratch the film like you wouldn't believe. Never clean negatives by pulling them through your index and middle fingers; I pull them, with very light pressure, through a folded Ilford anti-static cloth. Insert the negative into your negative carrier, dust it with a jet of air, and load it into the enlarger.
Your camera may be scratching the film, and the best way to check for that is to do a "scratch test." This test is often used in any environment where film is transported, such as motion picture magazines, film splicers, et cetera. To make such a test, run part of a roll of film through your camera, and without disturbing the the film, open the camera back. Inspect the film, and if you find a scratch, the film will still be "aligned" so that you can track down the source. It MUST be a fresh, factory-loaded roll of film. Do NOT USE bulk film (see below).
A common cause of scratches is the film pressure plate, which can cause base scratches. An emulsion scratch, which is a scarring or an outright gouging of the emulsion is sometimes caused by dirt or grit caught in the camera. I once searched for a deep emulsion scratch for hours, until I realized that one of the two flat springs which held the pressure plate on one of my motorized Nikon F cameras had sprung out of place!
Dirt on the felt lips of a film cassette will cause either base or emulsion scratches. If you get the lips dirty, the best solution is to reload the film into another cassette, and toss the dirty one into the recycling bin!
A word about bulk film: I had fine base scratches off and on until I stopped using bulk-loaded film. The film was clean; my cassettes, some of which were used during my student days in the 70's (I'm dating myself) were the culprits. As soon as I started using factory loads, my problems with fine base scratches disappeared.
-- Terry Brennan (firstname.lastname@example.org), April 06, 2000.