Newton rings revisited. Arrgghh...

[austin granger]

Hello all.

I realize that the problem of newton rings has been discussed at length before (I think I've read about everything that pertains to it) but I'm posting this in the faint hope that maybe someone's come up with The Definitive Solution since the last go-round. Also, to tell you the truth it makes me feel good to be able to rant about a problem that many of you have undoubtedly encountered (or is it just me?) and can relate to. When I start spouting off about newton rings to my wife her eyes just glaze over... Anyway, here's my trouble:

I'm attempting to make 8x10 contact prints using a Bostick and Sullivan contact printing frame. I'm getting terrible newton rings forming between the glass and the negative. I can see the rings clearly when tilting the frame at a certain angle in ordinary room light. The rings get better when I place the negatives backwards, but obviously this is not going to be a good long term solution. Many have suggested getting AR glass, which I did (Tru-Vue Museum). Unfortunately, the rings are as bad as ever. It does not seem to matter what type of film I use. The rings are not generally visible in the final prints except in clear, uniform areas. But even in prints without clear, uniform areas, just knowing that those damn rings are lurking in there somewhere bugs me... (it's here that my wife grows concerned about my mental state).

In any case, what now? Has anyone tried frosted glass? I've read that with the anti-newton ring glass, a faint pattern can show up on the prints from the etched texture, but I'm wondering if ordinary frosted glass might be better. How about the sprays? While it makes me nervous to be spraying anything on my negatives, at this point I'm getting desperate. Maybe it's the printing frame itself; too much pressure? It seems kind of strange that something especially designed for contact printing would have such a problem...

Any help, or even commiseration, would be greatly appreciated. Arrghhh!

[Oren Grad]

I've never been able to use a spring-backed contact print frame without getting rings. I think the problem isn't too much pressure, it's that the pressure is uneven - the springs exert their force at specific points, and the felt-covered wooden back isn't nearly rigid enough to redistribute the pressure evenly.

I've had my best luck with a simple sandwich - a piece of ordinary glass on the bottom, the negative and paper in the middle, and a piece of quarter inch optical glass, larger than the paper, on top. I can usually get ring-free prints that way.

For negatives smaller than 8x10" printed on paper 8x10" and smaller, I just use the glass cover from a PrintFile contact printer (designed for proofing a roll of 35mm negatives in a PrintFile sheet) that I had sitting around. For 8x10" negatives printed on up to 11x14" paper, I use a 12x15" piece of quarter inch glass obtained from Focal Point (www.fpointinc.com).

I should say that in sheet film I mostly shoot HP5+, which has a very smooth base side and is very prone to Newton's rings. Among other films I've used, the old TXT as well as Bergger BPF 200 both have retouching surfaces and in my experience were pretty much ring-free.

[darter]

Hi Oren,

Where do you buy large sheets of optical quality glass?

Thanks,

Phil

[Oren Grad]

Phil -

As I mentioned, I got the 12x15" glass from Focal Point (www.fpointinc.com).

Unfortunately, when I spoke to them a few months back about getting a larger piece to use in my forthcoming ULF experiments, they said that quarter inch optical grade glass had become so expensive that they weren't stocking it in very large sizes any more. So I may be forced to try pestering a local glass supplier to find as clean as possible a piece of ordinary glass and cut it to size for me without messing it up.

If anyone has a reliable supplier for very clean quarter inch glass in largish (say, 18x22") sizes, I'd love to hear about it.

[Brian Ellis]

I bought my 16x20 or so contact printing frame from Doug Kennedy and have never had a Newton ring problem. The glass isn't anti-Newton ring, I suppose I don't get the rings because I print 8x10 negatives and put the negative near the center of the glass. Plus the clamps are very strong. I don't know if Doug is still in business, I bought my frame about ten years ago and I don't have any contact information but someone else here might know or you could Google.

[Oren Grad]

Brian -

Both of my contact printing frames - 8x10 and 11x14 - were also made by Doug Kennedy. They're beautifully built, but they cause ferocious Newton's rings for me. Perhaps using a very oversized frame helps to even out the pressure in the center.

Newton's rings are a real challenge to get rid of, because there are so many pesky little things that vary from one darkroom to another and can affect getting the pressure just right.

For people who, like me, want to use a film with a very smooth base and don't want to spray gunk on the negative, I'm not sure there's any solution, other than possibly a heavy-duty vacuum frame for those who can accommodate one in their darkrooms, that would be guaranteed to work. Maybe not even that.

Probably you just have to keep tinkering until you find a trick that works in your darkroom...

[Eric Woodbury]

Austin, I suspect you are right -- that if you put a diffusor in contact with the neg and between the neg and the light source the Newton rings will go away. In this case it would not be the texture that cures it, but the perfectly diffuse light source. Your might try white plexi instead of the glass in the contact frame. It will cost you a couple of stops, however, and it might be thicker than your glass. Also, it is hard to see through the plexi for dodge/burns.

[Oren Grad]

As a side note, sadly, the website for Doug's firm, www.greatbasinphoto.com, is down now, with not even a cached page left on Google. Perhaps he's gone out of business - I know that he'd already stopped making film holders a while back.

[wfwhitaker]

Austin,



Last weekend I was printing in a friend's darkroom with a Bostick & Sullivan contact frame. I was told that the B&S frames do not provide even pressure. My friend's set-up included two layers of mat board between the back and the paper to help even the pressure. You might try doing that as a possible solution which would be inexpensive.



Add my vote to the others' for Doug Kennedy's printing frames. I have a couple of them and they seem to work well in addition to being beautiful. The last contact info I had for Doug was up in Lake City in the northeastern corner of California. Try this link: http://e.neilsen.home.att.net/dougkennedy.htm



Best,
Will

[Jacques Augustowski]

get the glass from an old scanner, its optical glass
Jacques

[Brian Ellis]

It's been a long time but I don't recall Doug Kennedy being connected with Great Basin, he was by himself in California, Great Basin was an entirely different company located somewhere else. Did Doug later join Great Basin or is my memory just completely off?

[austin granger]

Thanks to everyone for their thoughts.

I just returned from a few hours in the darkroom, where I tried just about every combination of materials (ar glass, non ar glass, contact printing frame, contact printing frame stuffed with mat board, my old crappy proofer, etc, ) to try and get rid of the newton rings. The setup that worked the best was, believe it or not, just placing my negative on top of a piece of foam board then laying an ordinary hunk of glass on top. Go figure. The simplest, most 'humble', pairing resulted in sucess.

Now why did I buy spend 110 bucks on the Bostick and Sullivan frame again? Well yes, I suppose it does look pretty nice...

[Diane Maher]

Austin,
What kind of prints are you making, alt process? (you never said) How can you see the effect of Newton rings on an alt process print? Would they show up as softer-looking areas in the print? I am doing Pd prints using the B&S frame, but am not having any problems (as far as I know), but I only started a few months ago. I did replace the glass that the frame originally had with some glass (normal glass) from a local glass shop because one corner was broken when I received the frame.

[Erik Sherman]

I don't know if this will work for contact printing, but I had problems with rings when scanning some negatives on an Epson 3200. I did some research on the Epson site and found a suggestion to turn the negative over, then to flip the image in Photoshop, which worked perfectly. Apparently the film doesn't sag this way.

So try the following: turn the negative over, then see if the rings are as bad. If not, then create a second negative that is mirror image of the first, and print with it.

[Oren Grad]

Brian -

On recalling Doug Kennedy as Great Basin, the error is mine - too much time staring at the screen yesterday, I guess.

Thanks very much to Will for jumping in with the correct link!

[Andy Eads]

I used to run a color copy shop and we would get Newton rings when copying glossy color prints. We solved the problem with baby powder. We would put a small amount of high quality powder in our palm, hold the print a few inches away in the other hand and lightly (very lightly) blow a bit of powder in the direction of the print. It seems the very fine powder kept the surface of the print from the intimate contact with the copier glass needed to cause those fractional wavelength interference patterns. The amount of powder was never visible to the naked eye.
Another thing to consider is the presence of oil on the surface of both the glass and negative. The spot of oil will cause the intimate bonding needed to produce a Newton ring. Try cleaning the film and glass with a good solvent like Pec-12. Good luck!

[austin granger]

Diane,

I'm making 'ordinary' photographs using fiber-based paper. As far as describing newton rings, it's a bit difficult; first off, there not really ring-shaped; more like irregular blobs. They show up on prints (especially noticible in uniform areas-think skies) as a pattern. You can often see the effect if you place a glossy photograph right up against a piece of glass and press them together tightly. That's part of what a mat cures-getting the print surface away from the glass. Unfortunately, with contact printing you oviously can't have such a space. Anyway, if you are not seeing any problems with your prints, then I wouldn't worry much about it.

As I wrote last night, I did manage to find a combination that seem to get rid of the rings while retaining enough pressure for sharp prints. I think Oren was right when he thought that the culprit(s) with the printing frame was first off that the felt back is not rigid enough to distribute the pressure evenly; I'm having much better luck by placing my negs onto a smooth piece of foam board and then simply placing glass on top of that. Secondly, I think the springs just don't make for even pressure. For even if I place foam board inside my printing frame, the rings are as bad as ever.

It's funny, having recently switched from 4x5 to 8x10, one of the things that made me happy was knowing that I'd eliminate once and for all so many of the frustrating problems I'd struggled with in the past; enligning my enlarger correctly, keeping my negatives flat in the carrier, etc. and now I'm finding all sort of new challenges (not the least of which is actually lugging my new camera around!) springing up. Well, tis the nature of the endeavor, I suppose. Three steps forward, two steps back...

[stephen arnold]

There is a powder made for this purpose called "Anti Set-Off Powder". it is (or was) manufactured by Varn. you don't dust your negative with it but rather the glass. a very minute dusting does the trick. it works.