I'm not really certain this is the right place for this question -- but I'll ask it here for now.
Those who've done darkroom printing for a long time probably remember at least hearing about Panalure. This was Kodak's panchromatic enlarging paper, intended for making silver gelatin B&W prints from color negatives. Given that graded papers "see" only blue light, and multigrade only blue and green (and in a way different from orthochromatic film products, too), they don't work particularly well to make prints from color negatives of full-color subjects.
Of course, the option always existed to print the negative onto panchromatic camera film or duplicating film, process by reversal or reprint to obtain a B&W negative -- but contrast control, exposure, and cost all worked against this (not to mention there would always be some loss of quality with each generation of copy). So, Kodak introduced Panalure -- enlarging paper with a panchromatic emulsion. Obviously, this was graded (controlling contrast with light color wasn't an option when all the light needed to show at the same contrast), but when Panalure came out, multigrade either didn't exist yet, or was a brand new, almost experimental material. One had to work in total darkness, of course, just as when handling panchro camera films, but you'd have to do that to make interpositives on camera film, anyway.
Panalure, however, disappeared many years ago -- it was always a niche product in a market that generally preferred color over black and white, and when film started to ramp down, niche products were the first to go (Panalure might have been gone before 2000, I don't recall exactly).
However, one of the things Panalure was best at, better than anything else ever, was paper negatives for in-camera exposure, either with a lens or pinhole. Unlike graded or multigrade enlarging paper, Panalure recorded colors much the same way as common black and white camera films. This made more difference with some subjects than others, of course -- but (for instance) apples and roses look much more the way we're used to on Panalure than they do on either graded or multigrade papers.
Relatively recently, another panchromatic material has been in use for in-camera and pinhole photography: RA-4 color paper. Of course, this is usually (in this application) developed by reversal, and shot with a filter pack that corrects the color balance, in order to produce a one-of-a-kind direct positive image, like a Polaroid but without the "instant" or the throw-away trash (of the old peel-apart kind). Several times, recently, it's occurred to me that part of the reversal process involves developing the RA-4 paper in Dektol or similar paper developer, to produce a black and white negative image before fogging with light and redeveloping in the normal RA-4 process, to yield a positive dye image.
What if the silver image were left alone, however?
Either fix the paper after the Dektol step, producing an ordinary paper negative (which would be a positive print if exposed under a color negative), or process like a B&W reversal, bleaching the silver negative image with something that allows fogging and redeveloping the previously unexposed halide to produce a positive silver image. End result, a panchromatic silver image roughly like having a single grade of Panalure.
Yes, there will be that small range of amber that still doesn't record well -- either lighter than it should be in the negative, or darker in the positive -- corresponding to the color of a color darkroom safelight (around 590 nm, give or take). Still, that's a more lifelike representation than everything from yellow through red printing that way.
Best of all, RA-4 paper is relatively cheap -- cost is similar to multigrade enlarging papers. Done in B&W chemistry, the overall cost would be about the same as reversing common papers, as opposed to Harman Direct Positive which is still orhtochromatic and costs more than some ortho sheet films.
I haven't had a chance to try this yet, but I probably will. Anyone else done it?
Those who've done darkroom printing for a long time probably remember at least hearing about Panalure. This was Kodak's panchromatic enlarging paper, intended for making silver gelatin B&W prints from color negatives. Given that graded papers "see" only blue light, and multigrade only blue and green (and in a way different from orthochromatic film products, too), they don't work particularly well to make prints from color negatives of full-color subjects.
Of course, the option always existed to print the negative onto panchromatic camera film or duplicating film, process by reversal or reprint to obtain a B&W negative -- but contrast control, exposure, and cost all worked against this (not to mention there would always be some loss of quality with each generation of copy). So, Kodak introduced Panalure -- enlarging paper with a panchromatic emulsion. Obviously, this was graded (controlling contrast with light color wasn't an option when all the light needed to show at the same contrast), but when Panalure came out, multigrade either didn't exist yet, or was a brand new, almost experimental material. One had to work in total darkness, of course, just as when handling panchro camera films, but you'd have to do that to make interpositives on camera film, anyway.
Panalure, however, disappeared many years ago -- it was always a niche product in a market that generally preferred color over black and white, and when film started to ramp down, niche products were the first to go (Panalure might have been gone before 2000, I don't recall exactly).
However, one of the things Panalure was best at, better than anything else ever, was paper negatives for in-camera exposure, either with a lens or pinhole. Unlike graded or multigrade enlarging paper, Panalure recorded colors much the same way as common black and white camera films. This made more difference with some subjects than others, of course -- but (for instance) apples and roses look much more the way we're used to on Panalure than they do on either graded or multigrade papers.
Relatively recently, another panchromatic material has been in use for in-camera and pinhole photography: RA-4 color paper. Of course, this is usually (in this application) developed by reversal, and shot with a filter pack that corrects the color balance, in order to produce a one-of-a-kind direct positive image, like a Polaroid but without the "instant" or the throw-away trash (of the old peel-apart kind). Several times, recently, it's occurred to me that part of the reversal process involves developing the RA-4 paper in Dektol or similar paper developer, to produce a black and white negative image before fogging with light and redeveloping in the normal RA-4 process, to yield a positive dye image.
What if the silver image were left alone, however?
Either fix the paper after the Dektol step, producing an ordinary paper negative (which would be a positive print if exposed under a color negative), or process like a B&W reversal, bleaching the silver negative image with something that allows fogging and redeveloping the previously unexposed halide to produce a positive silver image. End result, a panchromatic silver image roughly like having a single grade of Panalure.
Yes, there will be that small range of amber that still doesn't record well -- either lighter than it should be in the negative, or darker in the positive -- corresponding to the color of a color darkroom safelight (around 590 nm, give or take). Still, that's a more lifelike representation than everything from yellow through red printing that way.
Best of all, RA-4 paper is relatively cheap -- cost is similar to multigrade enlarging papers. Done in B&W chemistry, the overall cost would be about the same as reversing common papers, as opposed to Harman Direct Positive which is still orhtochromatic and costs more than some ortho sheet films.
I haven't had a chance to try this yet, but I probably will. Anyone else done it?