Curves for POP?

kejack · Oct 31, 2006

Hello all,

I was wondering if anyone here has had experience creating digital negatives on Pictorico OHP for printing on Centennial POP? I've begun to experiment with both POP and creating digital negatives, and I am looking for an adjustment curve that can serve as a good starting point. So far I have tried the Color Ratio curve as posted in Clay Harmon's article at www.alternativephotography.com/articles/art056.html, using a couple of variations (using the RGB colors for density ranges of 2.2 and 2.5, respectively). Both variations print very flat, however. Any advice is appreciated! I am printing on an Epson 2200, by the way.

many thanks,
Ken Jackson

clay · Oct 31, 2006

I am surprised they are printing flat. I used the recommendations listed in the article to print some Van Dyke's a few months ago, and they seemed to print pretty well. What color blend are you using? And you are applying the curve and then inverting the image? The other thing - how are you determining your exposure time? It is very easy to overprint these digital negs when doing a POP print.

kejack said:
Hello all,

I was wondering if anyone here has had experience creating digital negatives on Pictorico OHP for printing on Centennial POP? I've begun to experiment with both POP and creating digital negatives, and I am looking for an adjustment curve that can serve as a good starting point. So far I have tried the Color Ratio curve as posted in Clay Harmon's article at www.alternativephotography.com/articles/art056.html, using a couple of variations (using the RGB colors for density ranges of 2.2 and 2.5, respectively). Both variations print very flat, however. Any advice is appreciated! I am printing on an Epson 2200, by the way.

many thanks,
Ken Jackson

kejack · Oct 31, 2006

I made two negatives, using R50G100B0 (for "Some Palladium Papers) and R25G50B0 ("Salt and Albumen") as provided in the article. For each I first applied the curve then inverted the image before flattening and applying the color layer. I printed each one by inspection, facing open sky but not direct sunlight for about 5 minutes, following recommendation to overprint by up to 20% for POP. It's possible that I overdid the overprinting. While the highlights look pretty good, midtones are fairly muddy, and the "blacks" are not printed all that dark. The second print (Salt and Albumen color numbers) has just a little bit more contrast than #1. I should add that I toned each in B&S's Platinum toner for POP (although I probably should have just run untoned proof prints, I just wanted to see what would happen).

Ken

clay said:
I am surprised they are printing flat. I used the recommendations listed in the article to print some Van Dyke's a few months ago, and they seemed to print pretty well. What color blend are you using? And you are applying the curve and then inverting the image? The other thing - how are you determining your exposure time? It is very easy to overprint these digital negs when doing a POP print.

clay · Oct 31, 2006

Weird, it sounds like you are doing things the same way I have. You could try another test print at R12G24B0. That should be super-dense, about LogD 2.8 if I remember correctly. If your blacks are weak, it sounds like the prints may be underexposed. I'm sorry I can't be more help right now. I will run another Van Dyke neg in the next day or two and see what I get.

Clay

kejack said:
I made two negatives, using R50G100B0 (for "Some Palladium Papers) and R25G50B0 ("Salt and Albumen") as provided in the article. For each I first applied the curve then inverted the image before flattening and applying the color layer. I printed each one by inspection, facing open sky but not direct sunlight for about 5 minutes, following recommendation to overprint by up to 20% for POP. It's possible that I overdid the overprinting. While the highlights look pretty good, midtones are fairly muddy, and the "blacks" are not printed all that dark. The second print (Salt and Albumen color numbers) has just a little bit more contrast than #1. I should add that I toned each in B&S's Platinum toner for POP (although I probably should have just run untoned proof prints, I just wanted to see what would happen).

Ken

kejack · Oct 31, 2006

Thanks, Clay. I'll try another test print at the increased negative density you suggest and see what happens. Looks like the sun won't return until Friday here in NC, though, so I'll have to chomp at the bit until then.

cheers,
Ken

Digidurst · Oct 31, 2006

kejack said:
Thanks, Clay. I'll try another test print at the increased negative density you suggest and see what happens. Looks like the sun won't return until Friday here in NC, though, so I'll have to chomp at the bit until then.

cheers,
Ken

Hey Neighbor (Says one from SC)

kejack · Nov 1, 2006

Hey there--nice to hear from you!

Digidurst said:
Hey Neighbor (Says one from SC)

sanking · Nov 2, 2006

kejack said:
Hey there--nice to hear from you!

I am also in your area. Greenville, SC.

With the Epson 2200 I have found that the most contrast I can get from the RGB mix is with G-255, B-0, R-0, and that gives a maximum density in the UV of around 2.4, which is just enough for VDB. To get more than that I would have to blend in some black ink with a separate layer. You may just print in Color with a greyscale image because the black inks produce way more than enough UV density, about log 3.5 with default ink lay-down.

Sandy

kejack · Nov 3, 2006

Hey Sandy, good to meet you and thanks for the information. After some fits and starts over the past year, I'm still trying to wrap my brain around digital negative-making, especially with the several methods that are out there.

I don't fully understand the advantage of using color for some processes rather than black (either black ink, or "mixed black"), or how one determines precisely what color to use to obtain the best densities for a given process. Maybe I should go back and study Clay's article a little more...

cheers,
Ken

sanking said:
I am also in your area. Greenville, SC.

With the Epson 2200 I have found that the most contrast I can get from the RGB mix is with G-255, B-0, R-0, and that gives a maximum density in the UV of around 2.4, which is just enough for VDB. To get more than that I would have to blend in some black ink with a separate layer. You may just print in Color with a greyscale image because the black inks produce way more than enough UV density, about log 3.5 with default ink lay-down.

Sandy

kejack · Nov 3, 2006

A Eureka moment...

...or perhaps more appropriately, a "Duh!" moment: it dawned on me that while making the negative in PS, I should flatten BEFORE inverting the image. Yow. I have to plead sleep deprivation, 3 1/2 hrs the night before I printed on Tuesday.

Anyway, I will try again today with a new negative (just made it and it certainly looks to be a lot less thin), with the same color mix as on Tuesday. I've been looking at the discussion about ChartThrob, so I think I'll give that a try and see what I can come up with for further comparison.

sheepishly,
Ken

Digidurst · Nov 3, 2006

Oh, don't worry about it, Ken! We all get excited with our new processes but excitement doesn't cure bone-deep fatigue. I'll be interested to see a gallery post with the new neg. Have fun!

Curves for POP?

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