What Is / Do You Use for Paper Negs

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I am building a very large format camera from assorted process / graphic arts camera parts. I will be making very large negs, most probably just taped to the wall instead of an actual back. I may also adapt / design a vacuum back. Still working out the details.

What kind of negative material is available in large, preferably roll sizes and what to use for a "paper negative" as I have read others use. When I was shooting graphic arts copy with a room sized process camera we used high contrast negative film in rolls from Dupont and Agfa. Is there any of this stuff still around and can any of it be used for continuous tone?



-- Paul van der Hoof (paul.vanderhoof@losangeles.af.mil`), January 30, 2002



Besides using paper negatives....

Maco has some very large sheets of UP100 B&W film on offer and rolls as special order item.

See this link www.mahn.net in general and this one: www.mahn.net/prfilm.htm for specifics

10 sheets of 20x24 UP100 will set you back USD 150,--


-- huib smeets (hsmeets@plex.nl), January 30, 2002.

Paul, I just realized that both of the postings were you. I've got a vacuum back from and old process camera you can have. About 24" x 24" +- ?? Was going to use it in my photo darkroom but never got to it. I'm an old printer (lithographer). Seems we have similar backgrounds. Here's another idea for you. Saw this done @ Color Media in Burbank, CA. They don't make enormous negs, they make enormous mural size prints. They project 4x5 negs or trans on to photo paper on the wall. The entire wall is a vacuum back. BTW it's in a large open dark room. Type R or C prints from a huge roll. 10" X whatever. and larger. -Steve

-- Steve Feldman (steve@toprinting.com), January 30, 2002.

Sorry, that should be 10' (FEET) not 10".

-- Steve Feldman (steve@toprinting.com), January 30, 2002.

Here's a test photo I took using a piece of Arista 8x10 RC paper. The paper negative was then contact printed on another sheet of Arista RC. Freestyle Sales Co in California sells mural size rolls of this same paper....the paper is very inexpensive and it has no writing on the back which is nice. Keep in mind that it will be very slow speed.



-- Eric Mims (eamism@mindspring.com), January 30, 2002.

Steve: I live in the Glendale area and frequent Burbank. If you anywhere resonable in SoCal I would be happy to take the vacuum back off your hands. I used to do camera work for circuit board etching. I also plan mural size prints as well using the same method you speak of. I don't expect to have a wall sized vacuum back however. Do you know who makes the color paper they use at Color Media?

Huib: Great. Thanks for the imput. I'll look into it.

Eric: Checked out your test 8x10 and looked pretty good. I haven't even tried the technique yet and was wondering if the contacts would be really soft or muddy due to light dispersion through the thicker paper. Is this all there is to a "paper neg" technique then, just use a printing paper without any marking on the back?

Good comments all and I appreciate the feedback.


-- Paul van der Hoof (paul.vanderhoof@losangeles.af.mil), January 30, 2002.

Paper will work fine as a negative, just remember that the exposure will take a while, so forget about "action" pictures. I once took a test shot (8x10) in my house using Polymax Fine-Art single weight paper. I rated it at ASA 6 and the exposure took 4 minutes at f22. I developed normally in Dektol, diluted 1:2. Instead of contact printing it, I scanned it and reversed it using Photoshop.

-- Steve Gangi (sgangi@hotmail.com), January 30, 2002.

I don't actually remember how much you can see the writing on the back of the paper...it may not make a big difference...I've always just used papers without writing. You should get pretty high quality results if you just remember that you'll be contact printing face-to-face (emulsion-to-emulsion). This gives you the correct orientation. Also, if you really overexpose the paper, you can still get a usable image, but you'll probably lose highlight detail...notice in my image, the white shirt...it didn't matter how dark I printed it, parts of his shirt had no detail.


-- Eric Mims (eamims@mindspring.com), January 31, 2002.

How large are you talking about though? You mention film & paper available in long roll, so I assume you mean mural paper here? making an 8x10 paper neg & pos print is one thing....but a 4x8 or so is something else.....we used to make murals by hand in-house and used sorta a "poorman's horizontal enlarger"--an MXT horizontally...and projected the images either onto a false wall in our lab (which is about 50 feet deep) and "tiled" together large sheets of mural RC paper...or in our older lab, we did it with a sheet of 4x8 plywood that hung off an overhead track....we had a sheet of 1 inch foamcore on the plywood and would use small pushpins to hold the mural paper in place...we used Kodak mural fiber based paper mostly (which is like a more durable s.w. paper) and would process the prints by hand in 2 nine foot Kreonite sinks that had risers built alongside...so you could "walk" the prints through to process...each sink had 25+ gallons of chemistry--one with dektol, one with fix.....you'd develop the print, pull the plug and turn on the water to stop...the sinks had water jets & standpipes built in...then you'd go to the fix sink & then back to the other and wash the living crap out of the print....murals are like color printing...pay a good lab to do them.

As an afterthought, probably a good paper neg material would be to use Kodak Ektamatic SC paper and an old Ektamatic 74RC processor....this paper develops in about 10 sec in one of those and is a single-weight fiber paper with no imprinting....if you fix & wash it later on it lasts so-so...it's heavily developer incorporated, so it has some problems there, but it would be like using a polaroid camera in a way but as a paper neg....the big problem would be in size...I think 11x14 is about the max on those papers & processors....and it will probably be the next item to be discontinued as well....I used these processors on & off in newspaper darkrooms years ago...they sold for about a grand new, but you can't even give them away now....

-- DK Thompson (kthompson@moh.dcr.state.nc.us), January 31, 2002.

oh yeah...as far as who makes mural paper?? All the big manufacturers do...Kodak, Ilford etc...Luminous has some nice ones as well...the max width is usually about 42 to 48 inches, although there may be some that are 52 inches tops...the length is 100 feet usually. We used (and still have some) Ilfobrom, Kodak Mural, Multigrade Rapid RC, Kodabrome Rapid...and we also used Kodalith in a 42 inch x 100 ft. roll. Most mural houses and pro labs are swithcing over to using lightjets now and running rc based papers through processors....doing murals optically is dying out fast, although there are still some places out there that do this....it's such a PIA though without a big processor....good luck with the project...maybe check out the surplus lots for state gov't in your area....I see alot of lab gear being surplused now....

-- DK Thompson (kthompson@moh.dcr.state.nc.us), January 31, 2002.

Thanks Everyone for all the GREAT advice. Will be checking these ideas out.


-- Paul van der Hoof (paul.vanderhoof@losangeles.af.mil), January 31, 2002.

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