April 18th, 2017, 11:27 PM
Experimenting with Piezo Pro curves – and emulating classic Agfa papers
I'm new to Piezography, attracted to the Piezo Pro inkset because it should be possible to simulate or at least approximate the tones of some classic darkroom papers. IMO this is one of the important things the new inkset could accomplish.
My initial concern is to come close to (or ’remanufacture’?) Agfa Portriga Rapid and Brovira. For many photographers these were the gold/silver standard of the era when all darkroom papers were heavy on silver (though near the end of their lifespan the Agfa papers diminished in quality). Portriga was warm-toned, and Brovira was cool black with OBs. Both came in glossy (#111) and matte (#118) surfaces. For fine-art printing they were normally selenium toned for archival preservation. This was a light or diluted toning that increased permanence and made a slight but quite attractive change in the tone of the print. And I happen to have vintage prints and a well-preserved set of Zone System patches of Portriga to compare with inkjet output.
For a portfolio I'm printing with a vintage look, I want to emulate Portriga Rapid 118 (matte) on Hahnemuhle Photo Rag. The initial obstacle I encountered was the slight magenta cast of the Piezo Pro inkset. Portriga depended on more Y and/or R for the richness of its overall BW tone. Epson ABW Warm actually comes closer to Portriga than PPro, but PPro offers noticeably smoother tonal transitions. PPro presumably inclines to magenta because Y ink is more inclined to fade. The cast that initially bothered me resembled the IJM sample prints of K7 Special Edition and Selenium, whereas Portriga's warmth looked more like the tones of K7 Neutral and Warm Neutral. I had to experiment to reduce this cast, which I could see at 5000K (but not at 6500).
Another feature of Portriga (especially with archival selenium toning) was a crossover from warm darks to slightly cooler highs, starting with Zone VI. PPro did a great job of following this crossover. I read somewhere (Manual? Blog?) that it might not be a good idea to mix PPro Warm and Cool curves without using some Neutral in the middle. By beginning this way I got a crude approximation of Portriga 118 on HPR with Highlights, Midtones, and Shadows set for 100% Cool, Neutral, and Warm, respectively. But after trying quite a few variations, I thought this blend looked best:
Highs = 100% Cool
Mids = 50% Cool / 50% Neutral (or alternately 75% Cool / 25% Neutral – hard to decide)
Shads = 100% Warm
In my trial runs I came up with some useful three-curve blends for HPR that didn't emulate any particular paper, but IMO produced better results than using one or two of the HPR Piezo Pro curves:
For what I thought was a desirable cool tone, skipping the Neutral curve:
H = 100 C
M = 100 C
S = 100 W
For moderately warm tone (as above, for Portriga):
H = 100 C
M = 50 C / 50 N
S = 100 W
And also a duotone that looks richly warm, rather like Piezo Carbon:
No split toning, just 75% W, 25 N.
I’ll work on emulating Portriga 111 (glossy, like a slightly smoother F surface) sometime soon, using Harman Warmtone Gloss. Its base and its surface gloss are a pretty good match for Portriga 111.
Apologies if it's presumptuous for a newbie to say so much so soon. These are just first tries. But to get used to the Pro inkset I had to try a bunch of curve combinations, and this note might give old hands some starting points on which they can improve. (And when you do, please let me know?)
Last edited by thompsonkirk; April 19th, 2017 at 12:04 AM.
Reason: Clumsy writing
April 19th, 2017, 07:15 AM
This is a great post!
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