I had a discussion recently on the Color Film & Developers forum concerning salvaging negatives from 30+ year old Kodachrome II that developed (as negatives) with a very dark fog-like density and eyeball-visible images that are too dim and soft in contrast to scan (and probably to print).
One conclusion that was reached was that next time I do this, I'd process the film with B&W reversal.
So, last weekend, I picked up a cubetainer of battery acid (which I've seen referenced as anything from 28% to 35% sulfuric acid) from the local parts store. No, not reagent grade, but it's been reported to work well in reversal bleach. I already had potassium dichromate on hand, purchased for alt-process printing. Sodium sulfite for clearing bath, and assorted developers, check.
Friday, I loaded a roll of Tri-X (expired 2001, slightly fogged, I think from sitting in my van in 90+ degree weather just after my move to North Carolina in late 2004) in my (1938) Balda Jubilette and shot for a while. There was a high overcast, giving relatively soft contrast; I metered for ISO 400.
Based on various web pages and the Ilford online processing instructions for reversal, I settled on the following process:
First developer: 10 minutes
Dektol 2+1, that's 2 parts stock to 1 part water, to mimic Ilford's recommended Bromophen 1+1; added 8 g/L hypo crystals and 4 g/L potassium bromide.
Ilford-style water wash (5, 10, and 20 inversions in fresh changes of water)
Bleach: 5 minutes
10 g/L potassium dichromate
12 g/L sulfuric acid (36 ml battery acid per liter of final solution)
(this is probably the most hazarous chemical I have around here, BTW -- familiarize yourself with the hazards before trying to mix this stuff; it's the only chemical I've used in the last two years for which I wear rubber gloves)
Ilford-style wash
Clearing bath: 2 minutes
100 g/L sodium sulfite
Short water rinse
Light exposure for reversal -- 2 minutes exposure to room light, alternating both sides of film
Second developer: 5 minutes
Dektol 1+1
Rapid fixer: 2 minutes
Ilford style wash
Photo-flo and hang.
The resulting diapositives look quite strong to the eye, and were fairly hard to scan (density too high to scan easily, even though my scanner usually does very well with relatively dense negatives). Excellent detail in dark areas, but skies pretty completely blown out. Pretty grainy (not surprising with Tri-X in Dektol).
Hanging behind me, probably dry now, is the second attempt. Based on reading the first strip, I shot the second test roll at EI 640, developed 20% longer in the same first dev, and used HC-110 Dilution F for 7 minutes as second dev. I'll report back with scans, but they have detail in the skies (not very strong, but definitely present) and still have excellent detail in all but the dimmest shadow areas. I may boost the EI another 1/3 stop, but I think I have the process nailed.
I'll attach a scan of one frame -- this is one of the better looking ones, because no sky to blow out. Of course, scanning tends to normalize the image, but it actually looks a bit better to the eye, held up against the light, than in the scan (because the density is on the high side for the scanner).
One conclusion that was reached was that next time I do this, I'd process the film with B&W reversal.
So, last weekend, I picked up a cubetainer of battery acid (which I've seen referenced as anything from 28% to 35% sulfuric acid) from the local parts store. No, not reagent grade, but it's been reported to work well in reversal bleach. I already had potassium dichromate on hand, purchased for alt-process printing. Sodium sulfite for clearing bath, and assorted developers, check.
Friday, I loaded a roll of Tri-X (expired 2001, slightly fogged, I think from sitting in my van in 90+ degree weather just after my move to North Carolina in late 2004) in my (1938) Balda Jubilette and shot for a while. There was a high overcast, giving relatively soft contrast; I metered for ISO 400.
Based on various web pages and the Ilford online processing instructions for reversal, I settled on the following process:
First developer: 10 minutes
Dektol 2+1, that's 2 parts stock to 1 part water, to mimic Ilford's recommended Bromophen 1+1; added 8 g/L hypo crystals and 4 g/L potassium bromide.
Ilford-style water wash (5, 10, and 20 inversions in fresh changes of water)
Bleach: 5 minutes
10 g/L potassium dichromate
12 g/L sulfuric acid (36 ml battery acid per liter of final solution)
(this is probably the most hazarous chemical I have around here, BTW -- familiarize yourself with the hazards before trying to mix this stuff; it's the only chemical I've used in the last two years for which I wear rubber gloves)
Ilford-style wash
Clearing bath: 2 minutes
100 g/L sodium sulfite
Short water rinse
Light exposure for reversal -- 2 minutes exposure to room light, alternating both sides of film
Second developer: 5 minutes
Dektol 1+1
Rapid fixer: 2 minutes
Ilford style wash
Photo-flo and hang.
The resulting diapositives look quite strong to the eye, and were fairly hard to scan (density too high to scan easily, even though my scanner usually does very well with relatively dense negatives). Excellent detail in dark areas, but skies pretty completely blown out. Pretty grainy (not surprising with Tri-X in Dektol).
Hanging behind me, probably dry now, is the second attempt. Based on reading the first strip, I shot the second test roll at EI 640, developed 20% longer in the same first dev, and used HC-110 Dilution F for 7 minutes as second dev. I'll report back with scans, but they have detail in the skies (not very strong, but definitely present) and still have excellent detail in all but the dimmest shadow areas. I may boost the EI another 1/3 stop, but I think I have the process nailed.
I'll attach a scan of one frame -- this is one of the better looking ones, because no sky to blow out. Of course, scanning tends to normalize the image, but it actually looks a bit better to the eye, held up against the light, than in the scan (because the density is on the high side for the scanner).