My bad, 46 pages!
I did use Kodachrome a little, I miss it too and liked it.
Reviving Ilfochrome (or a similar process) seems rather feasible.
It called my attention reading H.Wilhelm's book on image permanency that if Kodak chose to pursue Dye Bleach instead of Chromogenic printing we would have been much better off when it comes down to permanency. AFAIK; Cibachrome is very long lasting in dark storage and has decent display time too.
I'd have liked to see how it would have been if Ilford (Swiss) promoted its use more. Given digital tech (Lightjet printers) et al for correcting some of the quirks, it could have filled a niche for long lasting fine art printing. Drag down digital shooters in, and there is a big market.
Recall reading it was quite complex to produce; How feasible to manufacture by some small company or endeavor, don't know.
Sorry for the hijack, but Dan put this point and I thought it would be interesting about it.
The person with the eBay handle "jel8080" continues to spend not hundreds but now what amounts to thousands of dollars on expired Kodachrome film of all kinds, even 126....now why would anyone do that?
I've wondered exactly the same thing. And a common sense guess isn't difficult...
[Edit: Ooow... I just had an evil thought pop into my head... You don't think... Naw... Hmm...]
:devil:
Well, I have tried to get the Kodak data sheet with process and formula details. It seems that Kodak took it down. Using wayback.com, I am informed that there is a block on that information. It is apparently unavailable. Therefore, unless someone has the PDF for us, the patent is the only source of information.
And if no one is interested in trying to process Kodachrome, my offer of help still stands. I'm here. I'm not trying to herd cats.. I'm saying if you are hungry, there is food in the bowl.
I'm not trying to herd cats.. I'm saying if you are hungry, there is food in the bowl.
I assume programing is windows based....
THanks for clarifying PE.On the topic of dye bleach.......
Henry Wilhelm knows nothing about DB vs Chromogenic materials. The DB process is much more dangerous to use than any chromogenic prcess. DB materials were never possible to prepare with real camera speeds. It would take a family of shiftable dyes to make this possible. And finally, the grain in DB is at its maximum in medium to low density areas making the images you do get rather unpleasant. Kodak had a DB print process ready to go and its introduction date was 8 Dec 1941. It was called Azochrome.
PE
Kodak had a DB print process ready to go and its introduction date was 8 Dec 1941. It was called Azochrome.
Henry does know about how the permanence of dye bleach compares to chromogenic's, but not necessarily about use safety or designing a process. He also knows about Azochrome. See pages 25 through 29 of his book:...Henry Wilhelm knows nothing about DB vs Chromogenic materials. The DB process is much more dangerous to use than any chromogenic prcess. DB materials were never possible to prepare with real camera speeds...Kodak had a DB print process ready to go and its introduction date was 8 Dec 1941. It was called Azochrome...
Yes, that's in the same book pages too.Agfa did the same decades later and failed commercially too.
I'm not so sure he was wrong that a dye bleach negative paper like Cibacolor would have been much better than the Ektacolor/Fujicolor versions we've had to live with. Especially versions sold in the decades between when Ciba-Geigy decided against marketing it and 1993 when the book was released....POS-POS print systems have an inherent flaw. You are basically multiplying the slope of one curve by the slope of the other curve, (original slide x print material) to get the final dupe image. If your original has a perfect capture and a slope of 0.3, and if the print material also has the same slope, the result is a slope of 0.09, which is a reduction in contrast. This is why you must use masks to adjust contrast and masks to adjust color.
No pos-pos system without these masks has ever been a big success. Thus, high end labs or printers use masks and get superb prints but at a high cost in time and materials. So, most simple pos-pos printers have failed. Or, they had commercial difficulties.
I know Henry personally and we talked for about 3 hours on his last visit to Rochester. He is avid about what he does, but just like me, neither of us is always right...
I have to scream this from the rooftops I guess.
POS-POS print systems have an inherent flaw. You are basically multiplying the slope of one curve by the slope of the other curve, (original slide x print material) to get the final dupe image. If your original has a perfect capture and a slope of 0.3, and if the print material also has the same slope, the result is a slope of 0.09, which is a reduction in contrast. This is why you must use masks to adjust contrast and masks to adjust color.
I thought contrast increase is the problem in a pos-pos process. Now I'm confused.
Supposedly you can cook up a special developer which turns RA4 paper into pos-pos material.So, what we really could do with is a list of tips for using Portra (sheet, roll or 135, as appropriate) as an interneg or dupe film, in order to print from transparencies on to RA4.
I thought contrast increase is the problem in a pos-pos process. Now I'm confused.
So, what we really could do with is a list of tips for using Portra (sheet, roll or 135, as appropriate) as an interneg or dupe film, in order to print from transparencies on to RA4.
Several decades ago this was a standard part of our lab work, but there was/were specialist interneg film(s) from Kodak for exactly this purpose - they were discontinued years ago of course.
Ok, a reversal (1.5 gamma) printed onto the same stock is 1.5 x 1.5 or a final mid scale gamma of 2.25, a gamma increase in the mid scale, but in the toe it might be 0.3 so 0.3 x 0.3 = 0.09 which is a decrease. The scales are all out of whack.
A true print material is gamma 1.0 so that the mid scale stays the same, but still, the toe suffers. Whichever way, the dupe gets what we in the trade call a "dupey" look.
PE
So then dedicated duplication films would have been designed to counterbalance these "out of whack" realities? Or at least attempt to lessen them?
Ken
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