Is it possible to make a positive image (landscape) using tech pan 4x5 film?? Does anyone know where I can get a 4x5 slide projector?

-- Robert Janke (jankerg@uwec.edu), April 16, 2002

Answers

It would have to be processed with reversal. TMX renders beautiful results with Kodak's Reversal kit. Rate at iso 50 when shooting and prepeare for a 6 step, 45 minute process. TP would have to be experimented with and as for a 4x5 projector... I recall Polaroid made something like a stand that you would put on an overhead projector to project 4x5's. If it is still available, one only knows.

-- Scott Walton (walton@ll.mit.edu), April 17, 2002.

I agree with the above...TMX reversal is probably a better way to go...but had a thought on the projector...the poor-man's version might be to use an old enlarger....or a view-camera if you could get a lightsource on the back....I've used enlargers for horizontal projection in making murals...there's not much difference really in projecting a pos....depends on how far though.

-- DK Thompson (kthompson@moh.dcr.state.nc.us), April 17, 2002.

thanks for all the suggestions. I have used reversal process for films over the years but still want to experiment with Tech Pan. Need the 4x5 projector for presentations on barns. Am a member of a group trying to preserve historic dairy barns in Wisconsin and also a research grant for the same issue. A 4x5 presentation is impressive compared to 35mm. Thomas Lake, a local calendar photographer for years gave presentations with 4x5 color slides and they were unforgettable, thus my interest in using 4x5.

-- Robert Janke (jankerg@uwec.edu), April 18, 2002.

I do a lot of reversal processing of TechPan. If you search the archives of the B&W film procesing board you will find old posts of my protocols from a couple of years ago. In any event, here is my protocol:

Shoot at EI 12

Solutions: First Developer: 1:20 HC110 + 2grams per liter sodium thiosulfate

Bleach: 9.5g Potasium Dichromate + 66g Sodium Bisulfate. total volume 1 liter.

Clear Bath: 50g Sodium Sulfite. total volume 1 liter.

Second Developer: 1:10 HC110

Protocol: First Developer 10 min Wash 5 changes water Bleach 3 min Wash until water comes out clear (>5 changes) Clear Bath 2 min (max) Wash 5 changes water Expose 1 min each side to light Second developer 5 min Wash 5 changes water Fix 3 min Wash 5 changes water Hypo Clear 1 min Wash 10 min Photoflo Dry

This protocol gives about an 8 stop dynamic range which while a bit contrasty, gives good results for transparancies. E-mail me if you need more information.

-Fritz

-- Fritz M. Brown (fritzb7@juno.com), April 18, 2002.

Oops, the protocol should look like this:

Protocol: First Developer 10 min Wash 5 changes water Bleach 3 min Wash until water comes out clear (>5 changes) Clear Bath 2 min (max) Wash 5 changes water Expose 1 min each side to light Second developer 5 min Wash 5 changes water Fix 3 min Wash 5 changes water Hypo Clear 1 min Wash 10 min Photoflo Dry

Concerning 4x5 projectors, I know there were several made long ago. I have one made by American Optical and have seen an identical model produced by Beseler. They seem to be priced in the $500 to $1500 range for the ones I've seen for sale (but that could be considerably inflated over what you can get them for in the real world, if you can find one. Mine was given to me.)

Good luck -Fritz

-- Fritz M. Brown (fritzb7@juno.com), April 18, 2002.

Aaaargh! One more try 8(

Protocol:

First Developer 10 min

Wash 5 changes water

Bleach 3 min

Wash until water comes out clear (>5 changes)

Clear Bath 2 min (max)

Wash 5 changes water

Expose 1 min each side to light

Second developer 5 min

Wash 5 changes water

Fix 3 min

Wash 5 changes water

Hypo Clear 1 min

Wash 10 min

Photoflo

Dry

If it doesn't work this time, you can figure out for yourself where the carriage returns should be...

-- Fritz Brown (fritzb7@juno.com), April 18, 2002.

Try the DR5 process. DR5Lab in new york can run it through with either neutral or sepia developer. The results are quite impressive.

-- Eric (everheul@cnetech.com), May 02, 2002.

There are projectors that can work with large sheets of material, but if you want to make a large projection you should use a strong lamp and you shall end up burning your Tpan slide. Other materials are more resistant to high temps and can be used in large, strong projectors.

-- George Papantoniou (papanton@hol.gr), May 22, 2002.