Enlarged Negatives by Reversal, few questions
I have a large roll of 9.5" Kodak Aerographic Duplicating film, expired in '94 but I used it about 3 years ago and seemed quite fine. I'd like to make enlarged negatives for VDB as my largest format is 4x5. I have enlarged negatives before by making an interpositive and while this worked, it was tedious and very hit or miss. I wasted a lot of materials and the entire process did not seem so easily repeatable for me. On UnblinkingEye, there is an article entitled 'Negatives by Reversal/Less is more'. http://unblinkingeye.com/Articles/NbyR/nbyr.html
Is anyone using this method? I have a decently small amount of potassium dichromate, 10% and some Kodak Film Hardner (scrounged from a Kodak Royal Print Fixer kit) which contains mostly sulfuric acid. Any tips or hints otherwise? I've never tried anything like this but thought I'd ask before I go ruining all my pot. dichromate.
I have tried the direct method. I much prefer to make an interpositive because although it takes a little time it gives me extreme control over the DR of the new negative.
With a little practice it is possible to make the new negative in 15 or 20 minutes or less.
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I have used this method for quite some time now, worked out my own adjustments, compared it with interpositives, and though I did not use the Kodak film, but rather the Arista Lith, I do think it is capable to give negs of first quality which compare very well with interpos., let alone with digital negs.
direct positve/neg/whatever vs interpos
Originally Posted by Lukas Werth
i also have some freestyle i was going to try this with-intersetsing that you have been able to do it successfully which confirms my guess
years of working as a photomechanical artist for the most demanding adv clients taught me the value of direct pos in camera-usually however i was using the kodak products purpose made for this, and if i was working in a vacume frame, the regular direct duping emulsions for the printing trade were my main materials
it is so sad that the fine art foto folks have no knowledge of how all this is done every day in the trade
vaya con dios
I develop the original negative as a positive using a very similar reversal process, then use Arista Lith to make the enlarged negative. I expose the lith film with the positive image in the enlarger and process "normally" in Pyrocat-HD 1.5:1:100 or Dektol 1:2 if I need to boost the contrast. I keep TMAX 100 in 4X5 handy when I am shooting. If I see something that would be nice as a Kallitype, I shoot it in TMAX as well. I develop 4 sheets in the JOBO using the amount of chemistry one would use for a roll of 35mm or 120 film.
I can see the value of using Ed's process if all you have is the negative. However, if you know ahead of time you will be making enlarged negatives, it is worth shooting extra film and making the original a posititve. This means using 4gm of permanganate and 15ml of sulfuric acid per liter in closed tanks rather than the large quantities in trays described in the article for the reversal bleach.
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Doug, I never considered that sort of approach and honestly it might fit the way I 'work'. I normally shoot a few 'extras just in case'. I could get in the habit of shooting an extra. Would you happen to have any starting points or references? I'm a slow learner
Originally Posted by Phillip P. Dimor
I have done around 40 rolls of 120 TMAX 100 and 60 sheets of 4"x5" TMAX 100 over the past 6 months. I enlarge the positive slides onto APHS (Arista Premuim Halftone Supreme) in 8"X10" and 11"X14" sizes. I bought some 16"X20" APHS but have not used it yet.
Here is what I do to create the positives.
Get a T-Max Reversal Chemistry Kit from Photographer's Formulary. The instructions with the kit contain the chemical formulations of the developer(s), bleach, and clearing agent. If you like the process, you can mix the kit from component chemicals rather than buying the kit, which is what I do now. The formulas are from a 1998 (Camera and Darkroom) article and have been used by permission to make the kit. The formulas are also all around the internet, so don't be shy about your search.
Follow the instructions TO THE LETTER. Like jazz, you can't break the rules until you know them. That said - I have changed a couple of things to make the process work for me.
I use a JOBO with the 1500 series tank for 120 and the 2500 series tank that holds the 4"x5" reel. I develop only one roll or 4 sheets at a time using 500ml of chemistry in every step. More rolls and more chemistry per batch has not worked for me. I expose at 100 ISO for the TMAX (box speed!) and it appears to do well. The JOBO is run at 20C setting "P" rotation. Note that I did it manually quite sucessfully - I only use the JOBO to reduce the tedium.
Using the Photographer's Formulary Reversal Kit instructions, I pretty much follow them with the following comments/changes.
First Developer - 10 minutes in the JOBO (no change)
Rinse - (no change)
Bleach - I make up a solution of 4g Potassium Permanganate in 1 Liter distilled water (part A). Combine 250ml of the permanganate solution (Part A) with 250ml of very dilute sulfuric acid - Part B (235ml distilled water + 15ml battery acid from the auto parts store). NOTE: Mix up part B and combine with Part A right before use. Use distilled water and rinse all containers with distilled water for all of the bleach components. If there is chlorine or other stuff in the water it WILL NOT WORK. When you mix the permanganate with the acid, it should stay dark purple. If the color changes (turns clear) you have contamination. Stop. Remix your stock bleach solutions. Bleach 5 minutes per the instructions.
Clearing Bath - (no change)
Rinse/PhotoFlo - (no change)
Second Exposure - This is where things get exciting and strange. Pull the creamy yellow (!) exposed film off the roll and hold it near the overhead lightbulb for about a minute. Marvel at the strange looking negative. Move it back and forth. Put it back on a dry reel (can be very difficult during times of poor Karma). If you do not hold it up to the light the contrast of the film will be a lot lower. I have not fully explored the practical or cosmic consequences of significantly changing the amount of secondary exposure that the film receives besides expose/not expose.
Second Developer - The formula is suspiciously close to D-72 (Dektol), so it not only can be used for a second developer 1:2, it is an effective developer for your APHS during the enlargement stage if you want to REALLY boost the contrast of your negative.
At this point the instructions abandon you to "do what you normally do" to stop/fix/wash your film
Stop/Rinse - 1 minute 500ml distilled water
Fix - I dilute and use Flexicolor fixer from the big cheap jugs, but any fix should be fine. 5 Minutes NOTE: if you use Flexicolor fixer for your B&W work, there have been warnings to keep it seperate from the fix used in color work (I do what Ron (PE) says and have reached a higher state of darkroom enlightenment - thanks Ron ).
Wash - 10 minutes glug glug glug
Photo Flo - 30 seconds (off the reels)
Hang to dry
Whew! Now you see why a JOBO is helpful.
hard work+thinking hard
thank you for sharing the very hard work you have done to perfect a process-i like that you source non-photo sources for chems-much cheaper
Originally Posted by Dug
kodak method for reversal of roll film:
1-xpose and dev neg and bleach out
2-re-xpose remaining silver and dev; btw, you allready know what changes in xposure time will do
kodak makes sheet film pre-xposed so that any more xposure gives dupe
anybody can pre-xpose-'flash' any film or paper and make direct pos
if i can you can
vaya con dios