I guess if glassless works fine for someone then go for it. A few last points on this from my perspective:
I've never really understood this "extra 4 surfaces" thing when it comes to dust. If you carefully blow the dust off the glass and negative and immediately sandwich it, dust can no longer get in there. So although initially it takes a few extra seconds, once the carrier is closed you have the same two open surfaces to attract dust, just that these are glass surfaces instead of the base and emulsion sides of the film.
AND, since the glass is typically 2-3mm thick, dust collecting on the exposed glass surfaces is further away from the emulsion in either direction than it would be if it collected on the film itself. Combine this with the fact you can use a larger lens aperture, and the dust can often be out of focus enough that it becomes less of a problem.
Also as some have suggested, particularly with 35mm, adding just a top glass goes a long way since deformation is typically upward, so that would be only two extra surfaces.
I'm a fan of Anti Newton 4x5 Glass Carriers. They work with all formats up to 4x5! I just cut an opaque mask around the smaller format negs to prevent flare and center the cut out to keep the film in the center of the light source cone to allow me the use of that formats normal lens. Keeping the six surfaces dust free can take a little work and a humidifier in the room will help keep the air relatively static free and the environment is much more pleasant to work in.
Interestingly, I experienced Newton's Rings for the first time in my last darkroom session. I was printing a TMax 400 negative in the Leitz V35 enlarger, and it was the last negative of the particular strip of film, and more curly than usual. So I decided to use AN glass on the top to hold the negative flatter; I could visibly see it curl as it was in the neg carrier.
I got what I thought was a nice print, on a piece of 8x10 Ilford paper. Fixed it, toned it, dried it, flattened it, and scanned it. Lo and behold - Newton's Rings in the upper left hand corner. That had never happened to me before, and now I wonder how I'm going to print this nice negative without having issues...
Thomas, TMAX films and Acros can sometimes be tricky - in fact with these films you can sometimes get Newton rings even on the emulsion side because the emulsion is comparatively glossy. I've actually been corresponding with John Sexton on this issue regarding experiments each of us have been doing with a variety of different coated glasses. It has been an interesting project so far.
Anyhow - if you get the occasional problem on the base side (the usual place Newton rings show up), and you don't want to start messing with all sorts of fancy glass - a lot of the anti Newton rign glasses out there are crap - here's a simple trick I came up with, which I've posted about before:
Cut a piece of fully fixed, unexposed, undeveloped Tri-X 320 and sandwich it between the top glass and the negative. Since the base side of Tri-X 320 is designed for retouching, it is just rough enough (as is the emulsion side) to eliminate Newton rings under most circumstances. It works very well. There is light loss of about 1/2 stop. Hope this helps.
Thanks for the suggestion, Michael. I will try that some time. See if I can find a donor for an unexposed sheet of 4x5 TXP as I'd very much dislike to buy a whole box.
I can send you one already processed and ready to go.
Can you see the Newton Rings already on the photographic print or is it at first on the scanned result ? In that case it could possibly be Newton Rings from the contact between the print and the scanner glass. I know it sounds improbable as the print surface seldom is flat enough unless you ferrotype the print or use glossy RC-paper. It can be worth looking into.
Originally Posted by Thomas Bertilsson
I attached a picture to a post above where I've marked the rings in red.
Originally Posted by K-G