I would like to try to enlarge some 4x5 negs into 8x10 negs for contact printing. I know using digital with transparency film and scanner is all the rage, but I do not have the time or desire to go that route at the present time.

What is the film used and and who carries it? Also please recommend a web site or book that provides some practical how to info.

-- James Chinn (JChinn2@dellEpro.com), April 11, 2002

Answers

The process i am looking for uses direct duplicating film or transparency(?)reversal film to achieve the final negative.

-- James Chinn (Chinn2@dellepro.com), April 11, 2002.

The best book on the subject is Kodak's "Copying and Duplicating in B&W and Color", pub M-1. There are 2 methods used for this. One is to use the direct duplicating film, SO-132 Professional Duplicating Film. The other is to make the duplicate negative in two steps by first making an interpositive master and then contact printing that to get the working neg. In the Kodak book, they use both Kodak Commercial Film and Super-XX pan, as well as SO-132. All 3 of these are discontinued, SO-132 is on the chopping block now....you can probably still get it though. In 8x10, it will be close to $80+ for 25 sheets. It's about $45 a box for 25 sheets of 4x5.

Ilford Ortho Plus Copy Film is very similar to Kodak Commercial Film, so you can substitute this. From emails I've had with Kodak last year, they recommend TMX100 as the interpositive, and Tech Pan as the working negative, for 2 step duping. I have also had some emails with a lab that does large scale duplicating of historical negs & plates...they recommended Delta 100 Plus as the interpositive, and Ortho Plus as the dupe neg. I can send you the densitometer aim points if you're interested in them, otherwise here's a link to the vendor specs that the NARA uses:

http://www.nara.gov/arch/techinfo/dupspecs/blackandwhitenegs.html

The Kodak book is still the best on the subject, and will explain in detail both methods. I have used quite a bit of SO-132, and it can be a pain with certain types of negs--trying to match the tonal range of the original. It's slow, but it's an ortho film and you can use it under an enlarger much like paper...especially if you use a film holder or a black easel--flare can be a problem enlarging negs....you can tray process or do it in tanks in regular developers as well. ( I use DK50 1:1 in a tank) It's a positive material, so you have to think that way when you use it....more exposure equals a lighter neg and vice-versa. The film has to be processed exactly as Kodak indicates in the tech sheet...there were stability problems with earlier versions....Kodak recommends that you not use a hypo clearing agent with the film, rahter a full 30 minute wash. They also recommend either selenium or brown toning of the film as well. I have worked with older dupes made on the previous films like SO-015...they changed density & tone in storage....when I use SO-132 I do tone in selenium and go for the full washes....I'll let you know in 30 years how they've done....but most archives and historical institutions do this in 2 steps...the interpos becomes the master for safekeeping, the dupe negs becomes the working negs....you can dodge, burn etc on the interpos as well....

I have about a dozen boxes of SO-132, and still see 8x10 in stores...it never sells, it's sort of an oddball item. If you find some, you might want to stock up a little bit....good luck and:Opinions expressed in this message may not represent the policy of my agency

-- DK Thompson (kthompson@moh.dcr.state.nc.us), April 11, 2002.

You can make a dupe neg on Kodak's 6121 Duplicating film. I have made literally hundreds of duplicate B&W and colour negatives over the past 25 years using this method.

6121is a process E-6 film, so you will either have to send it out, or try and process it yourself. I would consider the former, but not the latter.

I have also used the two-step method described above, and it works well. The main problem is dust, which you will encounter at both the interpositive-making and the internegative-making stages. Dust on the interpositive will print white in the final print, dust on the internegative will print black.

I used to use TMAX-100 for the positive, especially when the original was a colour negative, as it wold maintain the correct tonal relationships of the original, and not give you an "ortho" or "colour-blind" look in your final print. You can still get this effect if you want, by use of filters when making the interpositive.

I used to use Kodak Pro Copy Film for the negatives. This film is a slow, orthochromatic film, which allows you to control the contrast both by development AND by exposure. For best results, testing is required. It may not be available in 8x10 sheets any longer, so another film will have to be substituted. Colour sensitivity is not required, so the film can be either ortho- or blue-sensitive.

Another problem you will have is getting enough contrast in your internegative. Your interpositive, if properly made, will be somewhat dark and VERY flat, to maintain all of the detail that was present in the original negative. To produce an internegative which has enough contrast to print, you will need to use Pro Copy and expose/develop for a fairly high contrast. Or, you could try another film which you can develop in a high contrast developer, such as Kodak D-19 or perhaps D-11. Higher contrast film/development will make any dust present all the more noticable, so your interpositive will have to be spotless. A difuse optical system will help in supressing dust.

Good luck; if you have any specific questions feel free to e-mail me, if you wish.

-- Terry Brennan (tbrennan13@hotmail.com), April 12, 2002.

Hey Terry, unfortunately Pro Copy was discontinued last year as well....I have heard (never tried) of people using it for duping glass plates though. The way it was explained to me was that the curve of the film in the shoulder, acted as a built-in mask more or less....my only experience with it is as a copy film....I agree that dust is a major problem though....you can probably still find some Pro Copy if you look hard enough, although from talking with some other people working in archives related photo depts, there was a bit of a run to stock up on Pro Copy last year....I don't think it will be easy to find a substitute for that film. my opinions only.

-- dk thompson (kthompson@moh.dcr.state.nc.us), April 12, 2002.

I know this is an old thread, but I just recently discovered this list...

There is an article on Kodak SO-132 duplicating film in the Jul/Aug 2001 issue of Photo Techniques, p. 47, which looks to be right up your alley, James.

\donw

-- Don Wilkes (don.wilkes@gems9.gov.bc.ca), April 19, 2002.

Get it while you can...SO-132 was discontinued this year....actually, it was discontinued last year as well, but coincidnetally came back to life after that PT issue came out.....at any rate, if you can find some, it will be close to $100 for a box of 25 sheets 8x10. I know a local camera shop in my area has had an 8x10 box in their fridge for some time now...I have used this film, and still do--I stockpiled it sorta....here's the Kodak tech sheet link:

http://www.kodak.com/global/en/professional/support/techPubs/f11/f11.s html

If you use this material, follow the instructions closely for pricessing. It needs to be toned for long term storage. It's an ortho film, but very slow. If you were using by contact, the speed is that of Azo. If you enlarge, typically it's a little faster more like a slow enlarging paper. Ctein's article is an interesting method, as far as contrast control goes...but to be honest with you, the film is a bad choice for really contrasty originals....

I sent him an email after the magazine came out asking why they were covering a film that was discontinued & he said they didn't realize it at the time, since the article was written several months prior...anyways, for duping up to 8x10 in one step, it was probably your only choice other than the one mentioned above, using Ektachrome. Good luck either way, and if you want the name of the local store, drop me a line.

-- dk thompson (kthompson@moh.dcr.state.nc.us), April 19, 2002.

If the traditional internegative method is not feasible for you, perhaps you would consider making enlarged negatives by reversal. I have an article on the process entitled Less is More. The process uses cheap Arista ortho litho film.

-- Ed Buffaloe (edb@unblinkingeye.com), April 20, 2002.