F*$%!ng! newton rings on my contact prints?

[wildbill]

Up until now I've been doing my 8x10 contact prints with just a hinged piece of glass. No problems.

Now I have a new contact printing frame (photographer's formulary) with clean glass and I'm getting newton rings on one particular area of the neg I'm printing today. I cleaned the glass and repositioned the neg but they appear in every print (in the same vicinity) about the size of a dime. That area of the print* is bright white tone I can't see residue or defects on the neg. How do I fix this?


*kentmere glossy fiber

 

[Shawn Dougherty]

I solved this problem by cutting a piece of TruVue Reflection Control framing glass for my contact printing frame. Print with the "rough" side down, touching the back of the neg. It's been bullet proof for me and should cost you less than $20 unless your local framer is a crook. =) Mine gave it to me for free. Good luck, Vinny. Shawn

 

[JBrunner]

Up until now I've been doing my 8x10 contact prints with just a hinged piece of glass. No problems.

Now I have a new contact printing frame (photographer's formulary) with clean glass and I'm getting newton rings on one particular area of the neg I'm printing today. I cleaned the glass and repositioned the neg but they appear in every print (in the same vicinity) about the size of a dime. That area of the print is bright white tone I can't see residue or defects on the neg. How do I fix this?

It could be a low spot in the glass. The rings are caused by incomplete contact. This can be cause by an imperfection in the glass, and often just by high humidity. You can try replacing the glass, increasing the pressure on the sandwich (try adding paper under your printing paper) lowering the humidity, changing to the bad type of old non-glare glass, or experimenting with other types of non glare glass (breaks up the harmonic) or blowing the bucks on anti newton glass. Personally I'd start with new glass and work up from there.

 

[wildbill]

Humidity is the los angeles type=LOW. As I said, I repositioned the neg to the other side of the frame and the rings show up on the same spot on the print.

 

[JBrunner]

Humidity is the los angeles type=LOW. As I said, I repositioned the neg to the other side of the frame and the rings show up on the same spot on the print.

Your probably getting rings elsewhere, they're just getting printed over. The stuff is all guesswork, and it is a maddening problem. I'll hold forth that the glass, the pressure, or the humidity in some combination are the problem. I used to get them here, and it doesn't get much drier. Went away for me when I went to a frame with more pressure.

 

[Akki14]

Maybe try what someone told me for enlarging and newton rings and rather conversely dust the glass and the negative with some baby powder or similar then brush off? Sometimes it's a bit of oil/ nose grease causing the newton rings and the dust soaks it up.

 

[jeroldharter]

If you use a frosted type, non-glare glass, isn't it hard to see where to dodge and burn?

 

[jp80874]

In an attempt to isolate the problem, have you tried other negatives?

Going another direction, the following older thread that I just happened to read recently on the LF Forum, is pretty critical of the contact frames from Photographer's Formulary. There are complaints having to do with uneven pressure which does seem to be the problem you describe.

http://www.largeformatphotography.i...ighlight=photographer's+formulary+print+frame

I have no personal experience with Photographer's Formulary frames. I have 8x10 and 11x14 sizes from Bostick & Sullivan and 7x17 made by Bill Schwab. After Photostock you have to wonder when he had time to make contact frames, but it works perfectly.

John Powers

 

[Neanderman]

Go to a frame shop and buy a piece of anti-glare glass.

Worked for me!

Ed

 

[Curt]

I never did read in the "Daybooks" that EW had a problem with Newton rings, I wonder what glass he used. It was not expensive I'm guessing, he was not that way.

 

[ic-racer]

This is how I do it for 8x10. I am using a glass (not a contact frame) and I start the exposure immediatly after the glass is lowered. The Newton rings move around a little before they settle in to a fixed pattern. So, if the exposure is in the 30 sec range the rings don't show up or are minimized considerably.

You should be able to see the rings by looking at the reflecton of the safelight on the film under the glass. Watch how they move around as you raise and lower the glass and you will see what I am talking about.

 

[sanking]

Best solution is to just replace the glass with the anti-flare glass available in framing shops as others have mentioned. There is no down side to this and it is a permanent solution that is 100% effective.

Sandy King

 

[wildbill]

I printed a few other negs and couldn't see any rings although those negs didn't have empty areas of even tone either. I'll replace the glass with the anti glare stuff. thanks everybody

 

[bill@lapetelabs.com]

HI wildbill,
Try Anti-Newton glass, I find that fpointinc.com is a good source. We buy our replacement glass for our Durst 184 glass negative carrier from them and they will cut and sand the edges to fit your needs.

 

[Andrew O'Neill]

Up until now I've been doing my 8x10 contact prints with just a hinged piece of glass. No problems.

Send the new one back for a refund, and go back to your old one.

 

[EASmithV]

As said before the ANR glass should help, but also try sliding a thin piece of board or thick paper in the edge to lift the glass up ever so slightly off the film.

 

[RJS]

So you went and bought the more expensive, purpose made one and fixed what wasn't broken! Welcome!

 

[EASmithV]

Best solution is to just replace the glass with the anti-flare glass available in framing shops as others have mentioned. There is no down side to this and it is a permanent solution that is 100% effective.

Sandy King

Wait, anti-flare glass totally eliminates newton ring problems? I know this seems like a dumb question, but I need to know before I go off and buy 20 lbs of the stuff lol.

 

[Nicholas Lindan]

There are two types of 'anti-flare/glare' glass sold by framing shops: one is coated with an anti-reflection coating just like a lens; the other is very lightly frosted and a bit like a soft-focus filter.

Either one will eliminate Newton's rings: the anti-reflection coating will reduce them because it won't reflect light back from the film surface and so there is much less constructive/destructive inteference; the lightly frosted glass will break them up because the distance from the glass to the film is always changing rapidly - for light a change in distance of 500 nanometers is considered monstrous. You only need the treatment/coating on the side that presses against the negative.

Another possibility that just came to mind, and I haven't tried it so caveat emptor and all that, is frosted Mylar. It comes frosted on both sides and if placed between the negative and the glass should completely eliminate the rings. The frosting is exceedingly fine and won't show as texture on the final print. A blueprint shop or art supply house should have/get some, an 11x17 sheet should cost no more than a few dollars.

 

[Captain_joe6]

I've been using a regular old sheet of 8x10 glass in an ancient springback frame, and the strange part is, when I'm printing in my home darkroom i get no rings, but when I travel across town and print the exact same negatives, I get rings all over.

 

[Sirius Glass]

Capt'n,

Can we assume that you are using the same notebook contact printer?

Steve

 

[Captain_joe6]

I'm not sure I follow entirely, but if I understand you correctly, then yes, it is the exact same frame and the exact same piece of glass. Strange stuff, those newton rings.