8x10 contact prints compared to 4x5 enlargements?

[Erik Larsen]

I’m of the opinion rightly or wrongly that humidity plays a big role in whether or not you’ll get newton rings. I’ve never seen them in my darkroom either contact printing or my plain glass negative carriers where as people doing things exactly as I do struggle with the nuisance. My humidity is always desert dry. I kind of feel blessed to not have to worry.

[Mark J]

Back in the 80's .....I don't remember how it all began, but I got into a conversation with Ron Wisner about this problem which resulted in my sending him a sheet of 1/4" plate glass that he sent off somewhere to have a single coating (same stuff used on lenses) applied to one surface. I don't remember it costing me much because I think he thought of it as a technical challenge to solve. Anyway, lot story short...got the coated glass, tried it, not a single Newton Ring since! Been using the same piece of glass for 40 years now.
So, you may be on to something with that coating idea.

Sorry I missed your comment Alan.
Yes, this is the key to it. With shiny film base and glass on top you have two reflections of about 4% or 4.5% . The fringe pattern is only generated when the surfaces come to within 2 or 3 waves of light apart ( for white light illumination ) , however there is a faint fringe pattern generated, now I haven't got the maths to hand right now, it might only be about 10% brightness modulation, but it's visible.
If you coat ONE of these surfaces and have it only reflecting about 0.5%, then the fringe pattern contrast will drop AT LEAST by a factor of 10. It might actually be 100, I will check my 'book of important things' while i'm working this week, if i get chance.

[Michael R]

Yes! I don't shoot much TMX, but I've seen Newton's rings coming from the emulsion side of 35mm TMX in the glass carrier for my LPL 4x5 enlarger, which has AN glass on top and regular glass on the bottom.

Yup. TMX has long been my favourite film (along with TMY-2) in all formats - except for the shiny emulsion which became an intermittent Newton ring problem for me when I first began experimenting with glass carriers. It’s what prompted my investigations into various potential solutions.

I did some wacky things. For my first go at a home-made 35mm carrier I had Schneider Optics (the U.S. arm in NY at the time) cut me some rectangles out of couple of B+W MRC UV camera filters. Another good one was contacting Tru-Vue and asking if they had a sample pack of all their glazing materials - which they actually sent to me for free (a bunch of 8x10s). Some funny stories along the way.

[Michael R]

Humidity could be a variable.

I know one photographer who found he could usually avoid Newton rings if he wiped the glass with isopropyl alcohol.

I’m of the opinion rightly or wrongly that humidity plays a big role in whether or not you’ll get newton rings. I’ve never seen them in my darkroom either contact printing or my plain glass negative carriers where as people doing things exactly as I do struggle with the nuisance. My humidity is always desert dry. I kind of feel blessed to not have to worry.

[Greg]

Humidity could be a variable.

I know one photographer who found he could usually avoid Newton rings if he wiped the glass with isopropyl alcohol.

Kodak Lens Cleaner applied to the glass reduces Newton rings.
Windex applied to the glass seems to increase Newton rings.
Kodak Film Cleaner applied to the glass and the film seems to work the best for me.
The above said, humidity seems to be a major factor that I have yet to pin down...

[Sal Santamaura]

...Kodak Film Cleaner applied to the glass and the film seems to work the best for me...

Do you have a stash of the old stuff? The type containing heptane and 1, 1, 2 trichloro- 1, 2, 2 trifluoro ethane?

[Alan Klein]

Yes! I don't shoot much TMX, but I've seen Newton's rings coming from the emulsion side of 35mm TMX in the glass carrier for my LPL 4x5 enlarger, which has AN glass on top and regular glass on the bottom.



This too. Interestingly, the instructions for my Epson V700 say to put film on the glass with the base side down, but also warn of possible Newton's rings. I do get rings, and so I scan with emulsion side down, despite whatever reasons Epson has for recommending the opposite. But for sheet film I use HP5 Plus almost exclusively. I don't know what I would do if I preferred TMX.



And this three. The take-home is just that one size doesn't fit all. If you've got an approach that works for you, count your blessings and enjoy being able to concentrate on making more pictures.

Wouldn't the picture be reversed if you scan with the base side up? Maybe that's why Epson advises to scan that way. Of course, you can reverse the image after scanning.

[Serge S]

Possibly museum glass would help, as it is coated on both sides with an anti reflection coating?

Sorry I missed your comment Alan.
Yes, this is the key to it. With shiny film base and glass on top you have two reflections of about 4% or 4.5% . The fringe pattern is only generated when the surfaces come to within 2 or 3 waves of light apart ( for white light illumination ) , however there is a faint fringe pattern generated, now I haven't got the maths to hand right now, it might only be about 10% brightness modulation, but it's visible.
If you coat ONE of these surfaces and have it only reflecting about 0.5%, then the fringe pattern contrast will drop AT LEAST by a factor of 10. It might actually be 100, I will check my 'book of important things' while i'm working this week, if i get chance.

[Greg]

Do you have a stash of the old stuff? The type containing heptane and 1, 1, 2 trichloro- 1, 2, 2 trifluoro ethane?

Exactly... Over the past twenty or so years, I infrequently used it. If I could smell it then I didn't have proper or enough ventilation.

Back in the late 1970s and the 1980s, we used it in normally ventilated darkrooms of (here it comes) a State Health Center, Hospital, and University!!!

[Jon Shiu]

Kind of cool looking patterns! Didn't show up in cyanotype print. Pictorico negative used.