View Full Version : anti-newton ring glass for scanning
Can someone steer me to a place to buy a piece of anti-newton ring glass that I can use in scanning large format bw negs? Does anybody have expericence in this i.e. will it eliminate the problem...?
David F. Stein
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Something to try before adding more layers for dust; I use neg holders made out of mat board. Cut 2 window mats that can support your neg and make a sandwich. It holds the neg 4 mils away from the glass.
From my experience in scanning 35mm slide sandwiches (several slides in the same mount) Newton rings usually appear with slides swollen by humidity. It doesn't normally matter that they touch, as long as they are relatively flat. The interference patterns happen when the slides are unflat and touch each other in bizarre ways.
I solved the problem by using an "anti-Newton device", ie, an air-tight plastic container with a 40 grams silica gel unit. After a day in the "device", negatives are perfectly dry and flat and much easier to scan. I only tested it in a 35mm film scanner (I own no flatbed that could scan a full 4x5) but it's worth trying.
thanks everybody for the replys. People are saying they get rings even without glass and without sandwiching negs or trans. So i still don't understand what it is that causes it. I do live in a humid place and that could be contributing to the problem (however, diminishes the dust , no?) I'll try taping the suckers down or making a holder out of something. THe glass if it worked would be by far the easiest and quickest so I'm going to send those folks in FL my question. Thanks again....!
Bob Salomon - HP Marketing
Newton rings are caused by a smooth surface - like the base side of the film - coming in contact with another smooth surface - like glass.
To reduce the possibility of Newton rings slide mount manufacturers apply a slight texture to the glass on the side that will contact the base side of the film - or sometimes to both sides. This texture, depending on the mount manufacturer is either sprayed on the glass or etched on the glass.
Home brew techniques to reduce Newton rings is to use corn starch or a spray made for Newton ring reduction or to space the film slightly above the glass - if this doesnot effect sharpness. Make sure you are handling and storing the film away from moisture or high humidity also.
I used to get Newton rings when I placed my negatives directly on the glass of a flat bed scanner. They were completely eliminated when I finally figured out that I shouldn't place them directly on the scanner glass but instead should use the negative carrier supplied by the manufacturer. I live in Florida, lots of humidity but the negative carrier fixed the problem. I don't exactly understand how you plan to use the ant-Newton glass but I would think that if your scanner didn't come with a negative carrier making something like Jim Galli suggests would be easier and less fraught with risks of scratches, dust, etc. than trying to use anti-Newton glass on a scanner not designed for it.
Ok, I'm going to come clean now. My problem lies in the fact that I am trying to scan long strips of 120 film. The film was not advanced the correct amount between shots in order to have each frame overlap the other, forcing a dialogue between the images. I don't want to cut the film, and I don'ět want to spend hours sewing together the individual scans. With the Epson 3200 I am able to scan a quarter of the film at one time (that is, of course, laying it under a piece of glass and not in the designated carrier which is big enough for only a 6x9). In this manner, I only have to cut the film once in the middle and I can scan the film by scanning first one end of the strip and then flipping it around and scanning the other. I still have to put those pieces together in photoshop but damage to the negs is a minimum and since I don't at this point know exactly where I will crop/cut etc... I want to keep the negs as whole as possible. 120 film does not always lay flat (and I do live in a very humid area, Italy, with lots of fog -and since the negs are almost all whole a lot of them are still curled up in loose rolls ). Some of the film has a real curve to it. It is not as rigid as a 4x5 or 35mm. Even if I make some sort of holder, I fear that the film will not lay all that flat. Granted I man shooting with a plastic camera and am not super super concerned with sharpness -looking instead for an emotional impact, I would like the ability to scan what I have on my film without the scanner doing it's part to add "emotion" i.e. out of focus images. It sounds like I can get the rings off the scanner glass as well. And what is it about the humidity that causes problems (other than mold!) or is this just one manner to keep the negs flatter? Someone on the Photo District News site thought folks here might be able to help me with the newton glass and that is why I brought my question here even though it is not strictly a large format question..... thanks all.
an alternative to jim's matboard is that floppy magnetic sheeting they make fridge magnets out of. You can get sheets off it cut off rolls at graphics places that make signs for a few bucks.
I find it especially good for 8x10 negs, otherwise I have to tape the neg to the mat board to "stretch" the neg so it doesn't sag and touch the scanning bed.
Just cut (cuts easily with a craft knife) two pieces the size of your flatbed glass, cut out the neg size, tape a hinge down the side and voila. the two magnetic sides "stick" together and hold the neg quite firmly and keeps it reasonaly taught. I still found there was a bit of sag with 8x10's so I stuck a thin cutout of matboard on the bottom in addition.
Placing the film emulsion side down on the glass will probably cure the newton ring problem. Most B&W films have a rough enough emulsion that this will work perfectly. A little black photo tape along the edges will hold it flat on the glass. Color film emulsion is smoother so this won't always work for color. You did say you are using B&W film didn't you?
Another solution is to mount the film with mounting fluid (as used for drum scanners) on the glass with an overlay of mylar. This would be difficult to do with your entire roll - but not impossible. It might give the very best result. But you will have to clean up a little bit of mess each time.
You might also try hanging your film for a day or two before you scan, it'll relax a bit and be easier to handle. Don't worry too much about the absolute flatness of your film, your scanner has a pretty good depth of field and will digest a little bit of curve with no discernable effect. Just get it flat enough and taped down so the base side does not touch the top glass of your scanner.
I wanted to update. I searched for the fridge magnet (not all that hard -will keep looking however) but didn't find any. Instead, opting to try a less messy method (less messy than oil), I bought a piece of plexi and cut it to the size of the scanner with a window in the middle the longest I could make it (since I am doing these long strips of neg). I've been taping the negs to the plexi with regular scotch tape. It takes a tad longer than my simple neg under the glass method of previous but not much. So far, no newton rings and the negs look pretty crispy. Again, I am shooting tri-x with a plastic Holga so it is difficult to comment on sharpness. The "kodak" on the edge of the film I might add is not super super sharp but it seems to me this is the nature of how it is stamped on the film. There is some bleed all around it. I mean, the white of the letters sort of bleeds into the surrounding black a bit, there is not a super sharp definition. But again, I don't think this is the scan. If it is, someone please set me straight. One thing about wet scanning. Can I do this directly on the scanner glass and how do I clean up afterwords, both negs and scanner? I am under the impression I just use wipes but I have negs back from being scanned and they are still a bit oily. I would imagine the scanner becomes a mess. Any comments?
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