Contact printing glass plates...?

[Roger Thoms]

I use the glass negatives in place of the original glass. Good contact, pressure no problem.

Exactly what I do, at least for the one J Lane plate I contact printed. Worked like a charm.

Roger

[Nodda Duma]

Paul - I have one of those orange printing frames. Yes, it seems to apply a lot of pressure, that is what I feared. I have a glass plate that got messed up in development. I'll experiment with it to make sure it won't crack.

Jason, when I laid one of your glass plates on my cyanotype paper, the plate was not heavy enough to make uniform contact all around, the paper was slightly warped after I had coated it and it dried. I think I will have to at least lay a heaver glass over it during the exposure.

Randy, gotcha.. I freely admit that I am a novice at contact printing cyanotypes.

[Jim Noel]

...And no problem with any newton rings? I know I got newton rings when I scanned a glass plate recently, I just assumed that could be a problem when contact printing with a printing frame.

Occasionally , but not often.

[koraks]

...And no problem with any newton rings? I know I got newton rings when I scanned a glass plate recently, I just assumed that could be a problem when contact printing with a printing frame.

No newton rings. I get them too when scanning if I put the shiny side of the plate down, so I just don't do that. No problem with contact printing though.
Edit: I must add that I put a thin sheet of mylar between the glass negative and the glass of the printing frame, mostly to prevent scratches, but maybe it also helps preventing newton rings.

[Robert Brazile]

I've been using my (old) printing frames (including glass) with my glass plates with no issues whatsoever so far.

Robert

[Carol C]

I have a 5x7 glass plate printer from the 1920s, if your interested I listed it over a month ago, or you might be able to replicate the basics. I used it 20 years ago and it worked fine. Where the silver flat piece is with the handle is what pushes down on the plate it has a piece of cotton like material that was glued to the flat silver it was about 1/4 " thick. Each one of the switches on the green front control 12 tiny bulbs for dodging and burning. Attachment 179463

[jnantz]

Just lay the plate on the paper. Works really nice (pardon my sad, amateur attempts)




To avoid newton rings on scanning, place emulsion side against the platen and flip in post processing.

yup

[lew]

Was the issue re Newton Rings ever resolved/explained? It seems to me that this might be an issue; I know it was with glass negative carriers in my enlarger.

[Alan9940]

When scanning glass plates, I put the emulsion side down against the glass bed and flip in PS, as suggested in an earlier post. Many, many years ago when I had issues with Newton Rings when analog printing in my darkroom Ron Wisner and I resolved it by having a sheet of plate glass single coated on one side (same coating used on lens elements.) I always thought these rings were caused by uneven contact, but I've also heard that humidity can be problematic in this regard; or, maybe, I just wasn't wearing my lucky underwear! Anyway, luckily I haven't had any ring issues in years...