Dust Marks on 4X5greenspun.com : LUSENET : Large format photography : One Thread
Well, Murphy's Law being what it is, I got some superb 4X5 black and white negatives using Ilford Delta 100 Pro and sure enough, there are those pesky white dust marks on the negative. Yes, I did all the pre-cleaning and so forth but it was dusty and windy where I was shooting, so in spite of my best efforts, I got dust marks on the negs.
Maybe this is a dumb question, but what are some preferred ways of eliminating these marks? If I print with the marks then of course they will print as black jagged lines. Better to carefully retouch the neg under magnification or come up with a "white-out" solution for the print? Any recommendations, or is this too broad a subject here? Any recommended products?
I always hated spotting and retouching so I got dust pretty much under control in medium format and 35mm. I had forgotten what an issue it is in 4X5.
-- Greg Jones (firstname.lastname@example.org), April 13, 2001
The Spot tone people have a pen which bleaches out and refixes prints, then you fill it in with dye the usual way. Per the many helpful responses I recently received to a related question, drugstore iodine can be diluted and used for this, with less of a staining problem than some other techniques. You can put an opaque red on the negative so you end up with white you have to spot (thus skipping the bleaching step) but people on this forum haven't got much good to say about that technique. Though somewhat off the specific subject of your question, I did follow recent advise to blow out the inside of the camera and dust the holder before insertion in the camera. Those two changes to my routine, along with pulling the darkslide more slowly to cut down on static, have helped a great deal. I don't know of a photographic equivalent of white out, I would think that on a glossy surface that would be pretty obvious.
-- Kevin Crisp (KRCrisp@aol.com), April 13, 2001.
if the dust marks are bad and nothing else works, you could have a high-resolution drum scan made of your negative, seamlessly touch out the dust marks on Photoshop, and then generate a new negative in 4x5 or even in 8x10 just to make sure you're not losing anything in the translation. if you need help on the photoshop end, let me know-- for high-end photographic work photoshop is a much trickier program than most people realize, and there aren't many out there who know how to use it right (i.e., no degradation in image quality from beginning to end). today's film-output devices are truly amazing for their sharpness; especially if you used an 8x10 output you would get a new negative that is in every way equal to (if not better than) your original, but with no dust marks. ~cj
-- chris jordan (email@example.com), April 13, 2001.
I have eliminated dust spots using Kodak Readyloads for my 4x5. This approach is about 2x the cost over tradtitional film holders. I just purchased a 4x10 back for my camera and will have to use films holders once again. So I have been think a lot about dust. What follows are my unproven ideas about dust that are based on a many observations.
1. What brings dust to film is pure and simple - static charge. Static charge occurs primarily on plastic surfaces under dry conditions. If you have film holders that are made of plastic then you will have dust problems. The problem is intensified in dryer western climates.
2. Metal surfaces will obsorb static charge. When you walk across a carpeted rug on a dry day at touch a metal door handle a spark will occur jumping to the door handle. Eventhough the handle is not grounded (as on a wood door) the charge still passes to the handle removing the static charge from your body.
3. Wood camera will have more dust problems then metal cameras because the metal body will obsorb charge that has built up on the film holder. Wooden cameras will not obsorb static charge on film holders and thus more prone to dust on film.
4. Moisture will help reduce static charge. Just recently of recievd a box filled with packing popcorn. The charge was so sever that I could not remove some of the popcorn from the box because it stuck to the box walls. When I sprayed the popcon with water, it fell off the walls of the box instantly and was easily removed.
Based on the above observations, and that I will have load film in the field, here is what I plan on doing.
1. Replace my plastic darkslides with aluminum ones, I have just gone to a metal shop and they are being cut as we speak. There is a shop in town that will anodize them in black .
2. I use to store my film holders in Ziplock bags. I have just picked up some conductive plastic bags used for holding PC boards at a local electronics firm. I will use those bags fro sealing my film holders instead of Ziplocks.
3. Before I load my film holders, I will wipe down my flim tent and film holders with a damp sponge.
4. I intend to place aluminum foil on the bottom of the film tent when I am loading film. Most film tents are made of nylon which is woven plastic.. The foil will absorb any static charge that may build up and cause dust.
5 I will iuse a thick brush made of conductive filbers to brush off my film holders.
Hope this help!
-- Stephen Willard (firstname.lastname@example.org), April 14, 2001.
Is it possible that your elaborate pre-cleaning steps are provoking static electricity? I wonder if a de-ionizer fan would be worthwhile to reduce static charges? I work in a photographic cleanroom environment where any dust at all can be lethal to the product, and we have de-ionizers all over the place. We've done tests, and efforts to remove dust using tacky rollers, wiping surfaces, etc., can raise huge amounts of static charge, thereby defeating the original purpose. There are other methods to reduce static charge, like using a metal fiber imbedded brush, Fred Picker's high-voltage brush, etc. How dry is your climate and darkroom; do you air-condition? Air-conditioners can make the air very dry, and this can also contribute to the buildup of static charge.
-- neil poulsen (email@example.com), April 15, 2001.
I bought a HEPA filter unit from Sears - mostly to help with allergies - and don't have anything of the dust problem I used to have.
-- John H. Henderson (firstname.lastname@example.org), April 16, 2001.