By Carl Weese
[Part I is here]
Some people claim platinum printing involves black magic. I won’t go that far, but it’s certainly as much art as science. That’s partly because it’s just plain complicated. The ideal of testing one variable at a time is nice, but it just doesn’t happen in the platinum darkroom. You’re always juggling multiple factors.
This past March, Hahnemühle sent me some sample packs of its not-yet-released Platinum Rag paper (HPR). I did a couple quick tests and liked it so much I requested more for my “Digital Platinum” workshop at CAP/Penumbra in New York. (Disclosure: Hahnemühle is now a partial sponsor—donated paper—for my CAP workshop, which is entirely appropriate because CAP is a non-profit educational institution. For my current print offer I’m buying my paper from B&H, just like anybody else.)
The paper behaved about as you’d expect if one of the oldest and most respected paper makers in the world put their mind to the task of creating a paper from scratch for the process. The surface is so easy to work with that students, absolute beginners, were getting nice smooth coatings right away when we opened the samples on the second day of the workshop.
HPR and humidity
A sheet coated with Pt/Pd solution needs to be carefully prepared for printing. You have to dry it off, but you need to leave enough moisture in the paper to support the exposure process. Just how much humidity you need depends on the particular paper. I knew from beta-tester reports that the new material thrived in lower humidity environments than most other papers, which was great because the CAP workspace tends to be dryer than most papers like. The students’ prints showed that the paper is faster (shorter printing exposures) than the old standby, Platine, and had significantly more contrast. I’d need later on to do some tests to modify my negative preparation to compensate for the higher contrast. Meanwhile the workshop participants were delighted to be getting nice prints in their first experience with the process, and to see the fascinating differences between the prints on Platine and HPR.
Back in my darkroom I did precise tests with a file that combines an abstract step tablet and a small real-world picture. This let me find the shortest printing exposure that gives a maximum black, and then let me dial back one of my print driver settings (for outputting the digital negative) to keep the higher contrast from burning out the whites.
Then I did other stuff for most of the summer. When Mike and I had gotten our possible Print Offer selections down to four or five, working from on-screen files from scans, I decided it was time to test print them. As much as I like Fabriano, I didn’t want to do a volume run of printing with a paper that needs pretreatment, and anyway, I thought these pictures would look better on the brighter, cooler-toned HPR. So I got a package of 22x30 (which cuts down efficiently to 10x19.5) and immediately ran into a sticky situation. Literally. When a coated sheet that seemed to be perfectly prepared was printed with my large UV light source and vacuum frame, the edges of the coated area stuck to the negative film. This is not a complete surprise. These films are made super-absorbent so they can handle extreme ink loads, which is why we can make digital negatives for platinum with them, but absorbent is more or less a synonym for sticky. So I tried again and dried the next sheet enough that it would not be successful on Platine or Fabriano. The picture printed fine, but the edges of the coating stuck. This was strange. I’ve never before had this issue relate to scaling up the size of the print.
I coated a small sheet for my standard test negative, dried it totally with a hair dryer, and printed it right away. No sticking, but no Dmax. That’s no surprise, and most of the tones looked amazingly good for a bone-dry sheet. I coated and totally dried another one, then let it rest for ten minutes in 60% humidity, then printed it. It stuck. Just at the edges. I developed it anyway, and the print looked great, but the negative was toast from sensitizer transfer at the edges.
The small community of platinum printers is very collegial and generous. I quickly found out that people working with HPR over the past few months liked to use the additive Tween20 with it. About Tween, there are people who swear by it, and people who swear at it. I’ve always been in the “at” group. I hate the way the solution “works” during the coating process with the additive, on most papers. (It’s a surfactant. For those familiar with the silver darkroom, think Photo-Flo on steroids.)
Well, if HPR came with an instruction sheet (it doesn’t) I think it would recommend the use of a surfactant. The action of coating was not badly impacted—the coating distributed and worked in more quickly. Most important, given fan-but-no-heat drying in a 45% humidity environment, it showed no sticking at all even in the hard pressure of the vac frame, and delivered a beautiful print. OK, problem solved.
That’s how you figure things out for platinum printing: experiments, limiting the variables as much as feasible, and a little help from your friends.
©2016 by Carl Weese, all rights reserved
Original contents copyright 2016 by Michael C. Johnston and/or the bylined author. All Rights Reserved. Links in this post may be to our affiliates; sales through affiliate links may benefit this site.
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Featured Comments from:
Andrea B.: "Carl, can you tell me a bit about Pt/Pd archival properties? Any particular framing or hanging suggestions? Thanks!"
Carl replies: Andrea, Pt/Pd is the most archival of photographic media (well, carbon transfer may tie for that honor). The print consists of microscopic particles of non-reactive Pt/Pd metals embedded in fine, 100% cotton paper. Standard archival matting and framing materials are fine. Avoid dry-mounting; the print will lie perfectly flat positioned with corners or a paper hinge. UV-blocking glazing is a good idea to protect the paper, and avoid display where it will get direct sunlight.
Subdued or special lighting is not needed. In fact, it makes me a little crazy when I go to a museum show of wonderfully archival platinum prints and find the curators have set the lighting so low I can’t see the pictures properly!