PDA

View Full Version : What is anti-Newton ring glass exactly



Duolab123
10-Apr-2016, 18:24
OK , I have been following the thread on Beseler negative carriers. I have my interest piqued about trying to make a glass 5 x 5 carrier that will allow me to print right up to and beyond the borders of a 4x5 negative. Make an enlargement that looks like a contact print. I have never liked glass carriers, dust, rings etc. I have a very nice Elwood 8x10, I could use it, but I do 99% of my enlarger work on Beseler 4x5 enlargers, one with a color head, the other with a Zone VI VC head.

What exactly is AN glass, is it readily available, is there a drop in substitute, will plate glass work etc etc.

I can do this myself, which means I will never get around to it. Or this sounds like a good project for SKG, in wonderful Woonsocket.

Probably the easiest way to do this is just make contact prints, and live with the size.

If I could get the glass I could just sandwich the negative between the panes from a quick fix

Just curious how others have approached this. Wise council appreciated. Best Regards Mike

Sal Santamaura
10-Apr-2016, 18:53
...Probably the easiest way to do this is just make contact prints, and live with the size...I'll let others answer your questions, but, just to burst your bubble, contact printing in no way relieves one of the Newton's rings bugaboo. Unless Kodak 320TXP negatives are being printed, rings will at some point rear their ugly heads, whether enlarging or contact printing.

Carry on.

Michael R
10-Apr-2016, 18:57
Most anti-Newton ring glass has a fine texture (usually etched). Certain optical or glazing glasses with anti-reflection coatings may or may not also help prevent the appearance of Newton rings, but the most typical type is the textured variety.

So, no, ordinary plate glass is not anti-Newton ring glass. However if that's all you have available, there are some possible workarounds in the event you have trouble with Newton rings (an example is TXP as mentioned by Sal above). Depending on materials, setup, ambient humidity etc. Newton rings may or may not be an intermittent problem, whether enlarging or contacting.

If you use textured anti-Newton ring glass, it is advisable to enlarge with diffuse light.

I haven't found dust to be more of a problem with glass vs no glass, but that's just my own experience for what it's worth.

One source for anti-Newton ring glass is Focal Point:

http://www.fpointinc.com/glass.htm

LabRat
10-Apr-2016, 19:35
AN glass is like Michael said, finely textured glass... If a large surface of glass had a smooth surface, another smooth material against it would be touching but make imperfect contact against it, with the rings from interference... Now if the glass was equally pitted across it's surface, the material would sit only on top of the tiny peaks of the glass, and there would be a tiny space in the valleys of the surface that would not make contact...

Some glasses are rougher than others, and tend to hold dust more and seem "sticky" due to it's sharpness, while some are smoother on the peaks, but might make micro contact rings on those peaks, so good glass is a compromise between those points... It was made by blasting the glass, and slight etching to a balance, but is becoming a lost art and the hydrofloric acid used to etch are banned for the most part...

Steve K

Peter De Smidt
10-Apr-2016, 20:27
You can also try anti-glare framing glass, the kind with a slight texture on one side. It works for some, and for others the texture comes through in the print. The advantage is that it's cheap and easy to find.

Duolab123
10-Apr-2016, 20:55
It just dawned on me I saved a 5x7 carrier from a Eastman auto focus beast I scrapped out, I will try this in my Beseler, if it works maybe I will take it to the next step. Thanks for the help and the source info on AN glass. Mike

Keith Pitman
11-Apr-2016, 06:02
Focal Point also sells some sizes on Ebay: http://stores.ebay.com/FOCAL-POINT-GLASS?_rdc=1

Jim Noel
11-Apr-2016, 07:16
OK , I have been following the thread on Beseler negative carriers. I have my interest piqued about trying to make a glass 5 x 5 carrier that will allow me to print right up to and beyond the borders of a 4x5 negative. Make an enlargement that looks like a contact print. I have never liked glass carriers, dust, rings etc. I have a very nice Elwood 8x10, I could use it, but I do 99% of my enlarger work on Beseler 4x5 enlargers, one with a color head, the other with a Zone VI VC head.

What exactly is AN glass, is it readily available, is there a drop in substitute, will plate glass work etc etc.

I can do this myself, which means I will never get around to it. Or this sounds like a good project for SKG, in wonderful Woonsocket.

Probably the easiest way to do this is just make contact prints, and live with the size.

If I could get the glass I could just sandwich the negative between the panes from a quick fix

Just curious how others have approached this. Wise council appreciated. Best Regards Mike

There is no way you can make an enlargement that looks like a a contact print. As the light passes through the lens there is always some degradation of the image, however slight.

Drew Wiley
11-Apr-2016, 08:47
For large format work, I recommend Focal Point anti-Newton glass. For high-contrast printing of miniature negatives, you'd have to scrounge for something with
a bit different pattern, like vintage Durst or Omega AN glass. Focal Point AN glass would also be fine for contact printing, but you'd want a fairly thick strong piece, namely 3mm thick. Coated glasses sometimes work in lieu of anti-Newton glass, sometimes don't. Some of our modern thin-emulsion films tend to be pretty slick on both sides. But some modern sheet films carry their own micro-texture either to facilitate scanning or act like a traditional retouch tooth. There are various
other tricks for handling this kind of scenario, discussed on numerous previous threads.

Drew Wiley
11-Apr-2016, 13:54
... and since this is obviously a discussion about film and filmholders, yet within a digital section for some reason, that can only mean all the additional complications of scanner versus scanner. Ya gotta pin down the big variables first, Stone. A basic contact print would speak way more accurately than anything
posted on the web.

Duolab123
11-Apr-2016, 19:11
There is no way you can make an enlargement that looks like a a contact print. As the light passes through the lens there is always some degradation of the image, however slight.

Man, You speak the Truth. I'm always so impressed with contact prints. I've laid away a bit of of Foma's chloride Azo substitute. I've made 8 x10 contact prints, really nice.

Bernard_L
12-Apr-2016, 02:53
You can also try anti-glare framing glass, the kind with a slight texture on one side. It works for some, and for others the texture comes through in the print. The advantage is that it's cheap and easy to find.
+1
Meaning glass, not acrylic. And as Peter de Smidt said, the kind that is slightly frosted, not the super-expensive vacuum-coated "museum" glass. I use a piece of anti-glare framing glass, cheap, tape 120 film to it (flatness!) in conjunction wit BetterScanning holder. Works, I do not see the texture of the glass. Make sure it is the frosted side that is in contact with the film. Of course, there is probably not one single type worldwide, so no guarantee that the glass from the framing supply shop at your place will work as well. You may have to try a few.