Some questions from newbie

PiezoDN Digital Negatives
1

Hi all,

I have started using the new PiezoDN and read all documentation. I intend to use the system on my Epson 9900. So far, I have seen there are only curves created for Hahnemuhle paper. I have seen for other printers, some ICC profiles have been created for other kinds of papers.

My questions are:

  1. (For Walker) - Do you expect to release some ICC profiles for Bergger - Arches - Revere Platinum for 9900 printer in the near future?

  2. Concerning question 1) , could we just use the ICC profiles made for the 4900 printer for all those other-than-hahnemuhle paper? After all, we are talking about the same use of inks?

  3. Why is it that paper variants are incorporated into the system by the use of ICC, and not by making a whole new quad curve with a linearization made on the different paper?

  4. In fact, going even further, when using a different paper, and in order to be really precise, shouldn’t we start with a Master curve, limit it, and then linearize? Why is it that we just take into account the paper-variable into a ICC profile?

I intend to start using Arches Platine on my Epson 9900, with Pd and Pt-Pd, and I do not know whether I should start from scratch from a Master curve or not.

Thanks so much in advance for your help. I hope I will be able soon to collaborate too with my findings helping the rest of the community of PiezoDN users.

Warm regards,

rafael

 

2

Thanks Walker for your quick and thorough answer.

 

For what I understand reading your answer, if I intend to process using Pt and Pd but non-standard workshop conditions on a series of paper, the most logical roadmap would be:

  • For a certain paper (Arches for instance) create a quad curve from scratch, starting from the curve you have made for Palladium (not the Master curve) + limiting the curve + linearizing the curve.

  • Creating for Arches an ICC profile just to make the contrast and tone more equal to the one on my monitor

  • For the rest of papers (Revere, Berger Cott and Hahnemuhle), NOT starting from the beginning (limit + linearization), but using the same quad curve of point a) and tweaking the printing with a different ICC profile tailored to each of these papers

Is this correct? Or would you start from limiting+linearizing the standard 990 Pd only curve for EACH individual paper?

Thanks again and kudos for the great work you have put together into this system,

Warm regards,

Rafael

3

This is correct, however you probably don’t need to go through the limiting process unless you are using NA2 in your chemistry.

 

best,

Walker

4

I’m sure your right Keith. You invented it after-all. I think I’m overly paranoid about NA2 in combination w/ Ammonium Citrate developer. I’ve seen some weird things. It was probably just one of those days (aka, not controlling all variables properly).

 

5

Thanks Walker and Keith.

Keith, what you mention is really interesting and I was about to ask about it… Na2. As you say, some other printers have told me they use a small amount just for clearing the highlights, with not much incidence on contrast. That being said, I suppose it is a matter of being really precise in terms of what “small” amount means… How do you use the Na2? How much you use? Do you also use it when printing with Pt and Pd?

On another note, I would like to make sure I understood correctly the logic behind the piezoDN in terms of contrast control… Tell me if I am wrong, but after reading the manual I get that the new PiezoDN system will boost incredibly the last patch of the 120 target so that no matter which printing process and darkroom conditions that patch will always block completely the light when exposed at the normal exposure time. So, basically, the important thing is to make sure the following patch is not white too, so that when the linearization takes place, there is some readable value. When that does not happen, then the limiting procedure that is mentioned on the manual is used. Is this correct?

Tomorrow I am going to start calibrating a whole new quad curve for Pt and Pd and my darkroom conditions… For what I have understood too, Walker mentions that I’d rather start using the standard PiezoDN curve for Pd only, and just calibrate, without having much need of limiting. However, wouldn’t the addition of Pt increase the contrast and then risk of blocking a few patches in the highlights? (therefore needing from some limiting). Second thing is, why not start with the Pt-Pd standard curve even if the percentage would be different?

Sorry for the basic questions, I am just starting with this great system!

Warm regards,

Rafael

6

Answer to question one: Yes. This is how it works.

Answer to question two: You won’t need to use the limit with the addition of Platinum (most likely).

Generally I say, take the easiest route. If it feels like you need to limit, then limit, but don’t assume it’s going to be hard when it might be easy.

Best,

Walker

7

1) (For Walker) – Do you expect to release some ICC profiles for Bergger – Arches – Revere Platinum for 9900 printer in the near future?

Everyone's darkroom is so different that really the PtPd-Default ICC that is in there is where you should start with any paper. These individual paper profiles are all about 3% different from each other but they were built for our darkroom so your darkroom will print much differently. In generally people should make their own ICCs.

2) Concerning question 1) , could we just use the ICC profiles made for the 4900 printer for all those other-than-hahnemuhle paper? After all, we are talking about the same use of inks?

Just use the PtPd Default ICC.

3) Why is it that paper variants are incorporated into the system by the use of ICC, and not by making a whole new quad curve with a linearization made on the different paper?

Linearizing a .quad makes all the printed tones align in a line. For Platinum/Palladium this generally makes the print too light visually. The ICC does some fancy math and matches the contrast of the print to the contrast of your monitor. It's essentially only a photoshop curve, not a real profile.

4) In fact, going even further, when using a different paper, and in order to be really precise, shouldn’t we start with a Master curve, limit it, and then linearize? Why is it that we just take into account the paper-variable into a ICC profile?

When linearizing a curve, always print the target without color management (no profile). You can use whatever curve works best to linearize. The master works well as a default if you are linearizing for some wildly different medium, but I suggest using the Palladium curve to linearize if you are doing it for Palladium/Platinum. Then you print another target through that linearized curve and built and ICC profile from that.

I intend to start using Arches Platine on my Epson 9900, with Pd and Pt-Pd, and I do not know whether I should start from scratch from a Master curve or not.

Use the Palladium curve.

Thanks so much in advance for your help. I hope I will be able soon to collaborate too with my findings helping the rest of the community of PiezoDN users.

Warm regards,

rafael

All the best!

Walker

8

I have to disagree with Walker regarding the use of Na2.

If you are using it properly, by which I mean diluted to the point where all it does is prevent fog, it will not increase contrast or shorten the tonal scale at all. In fact it lengthens the tonal scale very slightly. I first noticed this a dozen years or more ago when I first started using Na2 for contrast control for printing from original large format film negatives. I thought it was a fluke of measurement, but over the years I’ve repeated these tests so many times with always the same result that I am 100% sure it is not a fluke. It is most likely due to slightly better separation in the highlights with absolutely no fog, and a teensy bit higher Dmax as well. Fog does not always occur without the use of a restrainer, but it is common enough, and simple enough to solve, that it is useful for any Pt/Pd printer to know how to handle. I can post a graph later to illustrate this.

I think maybe I need to write an article about the proper use of Na2 (or restrainers in general) in the context of digital negatives. It is not necessary but it does have benefits. And if used in this way it does not require changing the ink limits. If used at higher concentrations it may indeed be necessary, but there is no reason that I can think of to do that.

But Rafael did not mention using Na2 so maybe this is going off on an unnecessary tangent.

9

Keith, what level of Na-2 do you find gives those salutary benefits? I typically just always print with very fresh FO and use no restrainer at all, but if you find it beneficial, I am curious about the amount you can use without causing any shortening of the print ES. Something like 1 drop of 2.5% Na-2 per 1ml of Pd??

10

Keith,

A blast from a year ago. In reading through the archives of this forum I found your tantalizing discussion of Na2, but the thread petered out before it became actionable.

What dilution(s) of Na2 do you use with the PiezoDN negatives, since the density range of the negative is pretty close to perfect after linearizing the .quad?

Is the Na2 added to the metal and sensitizer that goes on the paper, or in the developer?

Thanks in advance,

Mark

11

At CEP we use 1 drop of 1.25% NA2 for every 40drops of total solution (roughly).

It’s just enough to act as a restrainer and basically nothing (not much) else.

best,

Walker

12

What Walker said. And you add it to the coating mixture.

As for measuring, I switched to using plastic transfer pipettes (usually 1ml or 3ml) long ago when I realized that a drop not an accurate unit of measure. I do use droppers for my Na2 dilutions though. I use 1 drop of 1.25% Na2 per 2ml of total solution (1ml each of FO + Pd), which is close to Walker’s 40 drops.

The problem with drops is that the volume of a drop can vary depending on the size of the dropper opening and the surface tension of the solution. Assuming your droppers are actually the same, a drop of Pd is slightly larger than a drop of FO. This means that if you use an equal number of drops for each, you actually end up with more Pd than FO. If you experience any run-off or bleeding of the blacks in your print, this is likely the cause. You can check how many drops of each solution it takes to equal 1ml (or any known volume) by using a pipette to draw 1ml of solution and putting it into your mixing container, then using your dropper draw it up and then count how many drops you get. Last time I checked I got 16 drops of FO per 1ml, and 15 drops of Pd. (YMMV so best to check it yourself.)

2ml is what I usually use for an 8x10-ish image size on most papers. (HPtR could probably get by with 1.5ml.) But if you want to stay with drops, using Walker’s example of 40 drops, I’d go 21 drops FO + 19 drops Pd. Don’t forget the Na2 is also a metal salt!

Here is a link to the Na2 contrast control chart that I use. It was initially designed for printing analog large-format negatives, so it covers the entire range of contrast control. It also covers image sizes from 4x5 through 15x20. For digital negs, you only need to be concerned with the first row. I keep a set of Na2 dilutions that range from the 20% stock solution down to 0.3%. For digital negs a 5% stock solution is plenty strong enough. (Those are the 2 concentrations that B&S sells.)