I just received an old enlarger, and used it as a light source for contact printing my 4x5 negatives. Using the same set up, I.E. frame, paper, etc, I got very noticeable Newton's rings in my prints. I've never had them before, using the same components, other than the light source.
The enlarger is a Durst F30 condenser for 35mm film.
Is there something I should be doing different with the enlarger, as opposed to a more diffuse light source?
On the plus side, I can now dodge and burn prints, whereas I couldn't previously.
You can diffuse the light source by putting a piece of milk glass in the light path, like at the negative stage in your enlarger.
But the Newton's rings are a function of the contact between the film and the glass, and your light source should, as far as I am informed, not make a difference in this regard.
1. Are you using the same film? Some films are more prone to rings than others.
2. Are you using anti-newton-ring glass in your contact printing frame? Or are you using regular glass?
If you are using ANR glass, is the correct side of the glass in contact with the negative?
That's all I can think of. Good luck!
Are you using Photo-Flo? I found that normal strength Photo-Flo on 35mm makes Newton rings on my Durst 606. I dilute it twice as much and then quickly dip the film reel in plain water before hanging and squeeging. Worked for me - no Newton rings and still no water spots.
use vaseline or Newton ring spray. If you use vaseline , you must find cleaning solution , prepress drum scanner labs knows where to find the spray or solution or Google it.
Thanks all for some great replies and advice. I haven't had a chance to print anything in the days since I posted this, but will definitely try the tips I receive.
To answer Thomas's questions- I'm not using anti-Newton glass. I'm printing the same exact negatives with the same glass. So no new film. The reason I suspected the condenser is the fact that my prior method had light bouncing all around the room, and no collimation, with no rings appearing. It was just a thought I had.
For Bruce, I don't use Photo-flow, just distilled water, no problems with stains since I got my routine down.
I am printing the 35 mm negatives without a glassless carrier, so they have no issues, it's just my 4x5 contacts.
I'll try the milk glass, I'm thinking of replacing the condenser with a piece. That should give me more uniform results for all my printing, I would think, anyway.
I don't think, Mustafa, I can find that spray around here, and would be afraid to try vaseline. I'll see what I can find, spray-wise.
Thanks again, I really appreciate it.
Good luck! I hope that you find an answer.
It's difficult to believe that a change in light source would cause this to happen, especially if your prints have all been processed to the same final contrast. But I've been wrong before, and it's nice to find out when I'm wrong, because I end up learning something new...
Just musing here.
Newton's rings are the result of reflections between two surfaces, and are dependent on the frequency of the light.
So a change in light source could change the appearance at least of the rings.
They are interference patterns apparently caused by relative perfect/imperfect contact. A while ago I experimented with several different types of coated optical glass but nothing really worked well.
The problem is normally easier to solve in contact printing than in projection, because one can increase contact pressure, which sometimes helps.
I would not recommend sprays. They also require careful cleaning.
Elevated humidity is said to increase the likelyhood of getting Newton rings. One method some people use is a quick wipe-down of the glass, the negative base, or both with alcohol. This may or may not work, but is a much lower risk procedure than using A-N sprays.
Assuming the rings are occuring between the glass and the negative, one quick fix is to put a sheet of unexposed, fully fixed Tri-X 320 (TXP) between the negative and the glass. The base side of TXP has just enough "tooth" to prevent Newton rings. Actually this reminds me, I was going to send Thomas a few of these TXP A-N spacers a while back and completely forgot!
Unrelated, but Howard Bond told a story to us workshop participants. He has used glass holders in his enlarger for years and years and never had Newton rings. At Westminster Abbey, he made a photograph with the tripod on the actual spot where Newton is buried. When he put the neg in the enlarger, he had Newton rings!!
Newton rings are a constant headache in my foggy climate. Anti-newton glass is a must. Anti-newton spray is also available from scanner supply companies, but there's a technique to using it, and anti-newton powders have long been available, which are basically just finely sifted
corn starch (not exactly something I want accumulating in my darkroom).