The inter-positive should be low contrast or you risk building up too much contrast in the final negative. So perhaps you need only change the developer for the negative?
Yes that's my plan.. Stick to low contrast Diafine and switch to Rodinal for the negative. That will split up the process a bit so I'll just do the interpositives one night then set up the stuff for the contact printing of negatives the next night
I've had a nutty idea. I have a 4x5 film holder (Fidelity Elite) and I'm considering using it like a contact printer... I can slide two films into it fine and they hold flat but I'm not sure if they're flat enough without glass. I guess I'll find out. Just seems like a nice idea because I could even use the darkslide to help me do the test strips (I hate fumbling around with a piece of black card in the dark).
Can't one use graphic arts film? That'll certainly be ortho. Should be dirt cheap on ebay... and plentiful...! I THOUGHT I'd seen some development tables somewhere - indicating continuous tone development times for certain developers...(?)
I dunno the graphic arts film I saw on ebay (only found one auction though iwas using ebay.co.uk) looked like, um. plastic film. like mylar? Not anything photographic... Maybe I'm looking for the wrong thing by searching for graphic arts film.
The darkness isn't that bad, really, and I work in a temporary darkroom setup and I've not bumped into anything yet. I've been using my setup for so long that I can use it blindfolded so working in complete darkness isn't that bad and it just meant a bit more gaffa tape around a few things to make it very very lighttight. I intend on doing my own RA-4 prints sometime soon so working in complete darkness is something I'm going to have to learn anyway.
Very interesting topic. Please tell me if i am understanding the process?
Contact print a 4x5 negative with a piece of 4x5 sheet film to make a positive . Develop. Place positive in enlarger with emulsion facing down and expose onto a sheet of Ortho or apiece 5x7, 8x10 or larger sheet film negative? Develop that negative and use to contact print.
I know I am quickly stating what will take a lot of trail and error but am I on the right track?
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There are different ways of doing it. You could enlarge the interpositive and contact print that to another sheet to make the enlarged negative, or enlarge to an intermediate sized interpositive and enlarge that to the final interneg size.
The original can be any size, so you could go, say 35mm->8x10"->8x10" or 6x7cm->4x5"->11x14", etc.
If you have a large camera, another option is to make a small print rather than a film interpositive and then dupe that with the large camera.
I can understand that, but am I correct in the way i decribed it in my original post? the interpositive is the end result of contact printing an original negative of any size with another sheet of film? How would I then enlarge the interpositve? What would you suggest to enlarge it on to? Could i not take anyone of my negatives and install it backwards into the negative holder, emulsion down, so instead of getting a positive image onto lith paper i would get a reversed image onto lith paper? And then use this lith paper to contact print with?
David have we met? Were you at the freezing cold LF Central park shoot this past winter?
Yes, we did meet in that cold Central Park shoot (which finally convinced me that carbon fiber tripods are a good thing).
And yes, if you contact print or enlarge a negative to another sheet of film, you get an interpositive. Flipping the negative in the enlarger gives you a flipped image, but it will still be positive. You can make a direct enlarged negative by enlarging the original negative onto film, and then reversal processing the film (as you would for a B&W slide). There are instructions for that in an article on unblinkingeye.com.
Generally, you get a better result by enlarging the original negative to the interpositive, and then contact printing the interpositive or enlarging it further to another piece of film to make the internegative, than you would by contact printing the original negative to film to make the interpositive.
Most people do this using ortho film, like Ilford Ortho Plus (and Freestyle has some less expensive alternatives), since it's easy to work with in the darkroom, and there's no particular advantage to using panchromatic film for this purpose in general.
So to do this I would put my negative in the enlarger and project the image onto the easel at the size i wanted, say 8x10 then turn the enlarger off place the ortho paper into the easel and project the image onto the Ortho paper then develop the ortho paper as per the directions. I now have a positive on the ortho paper. I would then contact print the ortho paper with another piece of ortho paper to make an 8x10 negative. Then use the resulting negative to make a cynatype or other alternative process.
Thank you for your time!
I only have an up-to-medium format enlarger so what I've been doing is just enlarging onto 4x5" film for the interpositive then just contact printing onto another sheet of 4x5 film to make the negative. I know I read the slightly confusing article on unblinking eye that made the process sound harder, especially if you're enlarging 35mm (they suggest contact printing the internegative... I think I'd have a little difficulty trying to see if my "test strip" if I could even do it properly in the dark, was right. It's all well and good if you have a 4x5" neg to enlarge but it's not going to work in my case). I happened to bookmark a topic where David A. Goldfarb had described the process as enlarge onto film then contact print so that's what I tried.
Also, as you're working, always remember that it's going to be emulsion to emulsion so when you do your enlarging to make the interpositive, and you view it through the nonemulsion side like you'd normally do, it will look reversed, then when the film is dry you contact print them emulsion side to emulsion side and then you get your negative the right way around.
So what you said in your most recent post is correct - just remember to dry the interpositive to be absolutely bonedry.
Where do you guys get your cheap lith film? Because from my searching around on various websites over here, it still seems like fomapan 100 is the cheapest sheet film around at 17UKP/50 sheets in 4x5. So that's 34pence a sheet or about $0.68 USD (at the moment). If I could get lith film that cheap, I'd use it.