Platinum Very dense neg


I just printed my first 129 steps target using the standard Pt/Pl Curve (on PPEv2/ Epson 3800) and I’m getting a very dense negative, my highlights on my print are blown by 30/35%.

I tried to create a limiter Tab file but the result is another .txt file saying that “The Lab values are not in order.
Cannot be linearized.” , I’ve tried to create a limiter file Dragging the 2 files to QTR-Linearize_Data droplet with different values and always have the same result " The Lab values are not in order.
Cannot be linearized."

Any ideas of what I’m doing wrong ? and why my negative is so dense using the master file?

Attaching pics of the negative and the limiter film Dense2 Dense1 print

Thank you


please upload your .txt file so I can see it.


Here are some tab delimited I created and some resulting files from QTR-Linearize_data.

Thank you Walker

Pro-PiezoDN-Master.quad-out.txt (1.2 KB) Pro-PiezoDN-PtPd-LIM_Test3-out.txt (14.5 KB) Pro-PiezoDN-PtPd-LIM_Test3.txt (2.6 KB) Pro-PiezoDN-PtPd-LIM_Test2-out.txt (14.5 KB) Pro-PiezoDN-PtPd-LIM_Test2.txt (2.6 KB) Pro-PiezoDN-PtPd-LIM_Test.txt (2.7 KB)

Hi Moises,

Please forgive me for butting in, but you mention at the beginning that you have PPEv2. I am confused, though, because you seem to be trying to apply PiezoDN v1 methods. PPEv2 does not use the QTR droplets at all. Also, did you mean to write QTR-Linearize-Data, or did you mean QTR-Linearize-Quad? The latter is the correct one.

Edit: I just looked at the -out files that you posted and that is what you get using the QTR-Linearize-Data droplet, not the QTR-Linearize-Quad droplet. Try again using QTR-Linearize-Quad. But more importantly, be sure you are using the correct quad to begin with – I can’t tell from the file names. If you actually do need to limit on of the starting Pt/Pd quads, there are 2 ways to do it depending on which spreadsheet version you want to use.

If I understand the issue, you are using PiezoPRO ink in a 3800 and getting an initial result that is substantially too dense using what you refer to as the standard Pt/Pl curve. (Note: The correct abbreviation for palladium is actually Pd, not Pl.) You don’t identify the curve by name, and there are 2 possibilities in the curves folder – one for develop-out chemistry and another for print-out chemistry – and they are quite different. I wonder if you might be using the print-out curve with develop-out chemistry, since that would indeed produce a result with blown-out highlights.

Screen Shot 2020-02-18 at 11.24.12 AM

It would also be useful to see your measurement file, as well as the CGATS text file that you already posted.

Sorry if I’m barking up the wrong tree. :wink:


Hello Keith

Thank you for your help!

1.-Yes I’m Using PPev2 on a Epson 3800, I don’t know how to limit the master file in this system, can you guide me on this?

2 I’m printing Palladium+Ferric Oxalate+Na2/ Developing on Ox Pot

3.- I printed the target using the " Pro-PiezoDN-PtPd-DevOut" curve and my standard exposure time (measure it with a LightMeasure UV Exposure Meter and a Amergraph ULF28 unit (around 5 minutes))

4.-Yes, you are right I was dropping the files on the wrong app (QTR-Linearize_data), dropping to QTR-Linearize_quad is working fine now.

5.- I don’t have any measurement file yet , I just printed the 129 target using the “Pro-PiezoDN-PtPd-DevOut” curve when I saw that I should limit my density I started thinking on the process and make some initial test of how to limit the density.!

6- Do you think its OK to have my highlights blown using my actual Analog+digital setup (see image attached)?

7.- Before Installing the Piezo inks I was working with OEM inks on the same printer using QTR and the quad file attached, and my tonal scale was very good.

PALADIO_P800_Revere_Ini_GC_3800uv.quad (5.8 KB)

Thank you again!


Moises Levy

We us 1 drop of 5% NA2 per 40 drops of solution . .


Hello Walker:

I use 20 drops F.O+20 Drops Palladium+5 Drops NA2+4 Drops of Tween 20%.

How should I limit the density if I´m using PPv2 ?
Should I limit the density or there is something else I´m missing?

Thank you


You are using way to much expensive NA2, NA2 is used to slow down (make less sensative) your platinum so you can print thinner negatives. Not needed here. Use 1 drop of 5% NA2 for the 20/20 drops of solution. Tween can probably stay the same.


Ok Walker I ´ll give a try with less Na2, ( you said you use also 5 drops of Na2 for 40 drops of solution ?)

If I need to limit the density in Gravure should I use the QTR-Linearize-quad droplet? or there is another way if I´m using PPv2?

Thank you !

Moises Levy

we use 1 drop of NA2 that was diluted to 5% strength in water. So essentially .05 drops. Really nothing, it’s just to keep the chemical fog down and nothing else. This is on @jkschreiber’s recommendation (essentially the originator of NA2).


I´ve printed a new target using your Na2 recomendation (1 (5%) drop for every 40 drops of solution) and my scale looks pretty good, except that it is too brown, I believe I´m working almost with pure Palladium ! , I´m thinking that maybe I should double the Na2 and limit a little my negative to remove somtheing of the brownish tone, what do you think?

Thank you


If you add 20% platinum (instead of NA2) and make sure your Oxalate dev is not too warm (about 65 deg F) it should be ok. The NA2 (more expensive than platinum) is causing the more neutral look but all you need is a bit of platinum.

Alternatively you could dev in Citrate dev for complete neutral.


Thank You Walker! much appreciated.

For limiting the negative density for other process it is Ok to do it using the Data-Linearize-quad app if i´m using PPEv2?



With PPEv2 you can draw a custom curve directly into the .quad . . .


Thank you Walker, with so many information on your website I got lost :slightly_smiling_face:



Aw shucks! I wasn’t the originator of “Na2” – that would be Richard Sullivan – but I was an early adopter 20-some years ago. It was very useful for those who printed from large-format film negatives and needed to be able to adjust contrast accordingly. For those whose negatives tended to be on the thin side, it was especially useful since it didn’t suffer from the graininess that tended to accompany higher contrast levels of potassium chlorate.

For people who aren’t already using it, I don’t think it is even necessary, since the only purpose it serves with digital negatives is to prevent chemical fog from ferric oxalate that is starting to turn ferrous, and for that we use it at or near the minimum effective level, which in my darkroom is even less than what Walker recommends – 1 drop of a 1.25% Na2PtCl6 solution added to 1ml of FO + 1ml of Pd solutions. 1 drop of a 0.6% solution of potassium chlorate should produce the same effect according to tests I performed a long time ago to correlate the various methods of contrast control that I used. Whatever restrainer you use, it is better to use a fixed volume of whatever % solution is needed. Using multiple drops of what is mostly water dilutes the mixture.

Why milliliters and not drops you ask? (Actually I use microliter pipettors for everything these days.) Well, what exactly is a drop, I reply! Is a drop of this the same as a drop of that? Only rarely it turns out. How many drops of each of our solutions per ml?

  • Ferric Oxalate — 20 drops per ml
  • Pd Sol’n (15%) — 18 drops per ml
  • Na2PtCl6 (5%) — 16 drops per ml
  • Tween 20 (5%) — 40 drops per ml

Why the difference? Surface tension. (And possibly but to a much lesser degree variation in the droppers themselves.)

Maybe you can start to see some potential problems. The main problem is that you are not actually using equal amounts of sensitizer and metal solutions – 20 drops of Pd is more than 20 drops of FO – and this can result in bleeding off of the excess Pd which can stain highlights and uncoated paper. If you do experience bleeding, the solution is usually to reduce the number of drops of Pd 1 drop at a time until it stops.

Now coming around to the question of image color and how to control it, I want to say loud and clear that Na2 is not compatible with the standard K2PtCl4 platinum solution used in Pt/Pd printing. What (unfortunately IMHO) came to be called “Na2”, is actually a platinum salt Na2PtCl6 that is a very powerful restrainer, hence its usefulness for contrast control, but it does not form an image by itself. So to get a cooler, more neutral, image color you have 2 choices:

  1. Use ammonium citrate developer. With everything else the same, this should produce a substantial change in image color towards cool. It will also print with higher contrast, and probably require an increase in exposure of up to 50% depending on the paper being used.

  2. Use a mixture of platinum and palladium solutions – a 50:50 mix developed in potassium oxalate will be much closer to neutral. If you want it cooler still, either use ammonium citrate or increase the ratio of Pt to Pd, or both.
    Note: You will not be able to use Na2 with this method, since it reacts badly with the standard platinum solution causing grungy highlights. Try without any restrainer first. Use potassium chlorate only if needed to prevent fog.

General rules of Pt/Pd image color:

  1. Metal: Platinum is cooler; palladium is warmer. Standard solutions of K2PtCl4 and Na2PdCl4 can be mixed in any ratio for intermediate colors.
  2. Developer: Ammonium citrate is cooler; potassium oxalate is warmer.
  3. Development temperature: Cooler is coolor; warmer is warmer.
  4. Paper: Some papers print cooler or warmer than others.

I realize I may be telling you stuff that you already know, one of the hazards of posting in forums where you don’t know your correspondent(s), but I hope at least some of this is helpful.


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Hello Keith

Thank you for the complete information, is always good to know more!

I have some questions if you dont mind:

1.- Should I use Ferric Oxalate Sol. 1 and Sol. 2 with Pl/Pd ? or only Sol No. 1?
2.- Do you suggest to use potassium chlorate over any ammonium or potassium Dichromate as a restrainer? (in case of using Pl/Pd)
3.- May I expect deep blacks using ammonium citrate as developer?

Thanks a bunch


Hi Moises,

I wasn’t sure if you were familiar with the other methods so I tried to keep it as simple as I could. But since you are familiar with them …

  1. If you have FO 1 & 2 (or as I prefer to call them, A & B) then you would be using 11:1 if following a 12 drop schedule, or as close to that as is practical for whatever the total drop count for FO you are using. For example, using the 20+20 you stated earlier it would be 19:1 or 18:2. If you don’t already have FO #2 mixed, it is perfectly feasible to keep the potassium chlorate as a separate solution and add it the same way you would add Na2.

  2. Both potassium chlorate and dichromate (ammonium, potassium, or sodium) methods are good. I used a 50% sodium dichromate solution added to the potassium oxalate developer for many years. (See the article on potassium oxalate on my website - it’s towards the end.)

  3. You should get similar Dmax with either developer. Deep is a relative term – it’s certainly not as deep as a silver print – but somewhere in the neighborhood of 1.40 density (~23.60 L*) should be typical.

Here is a table correlating all 3 contrast control methods:
Pt-Pd Contrast (43.1 KB)
There was a time when I used all 3 methods, sometimes 2 at the same time to obtain intermediate contrast levels.


Thank you so much Keith for the information, I really appreciate it.

How should I calculate the negative DR?
Do you have any table to calculate how much potassium chlorate to add ?



The table that I posted shows how much restrainer to use for each of the 3 methods. The table was originally made with large-format film negatives in mind, since that is the scenario where a printer needs to use contrast control as an important tool. For digital negatives, since we have the ability to take variation in negative contrast out of the equation, because we can make “perfect” negatives, the only purpose of the restrainer is to prevent chemical fog. Therefore we use it at the minimum level that is effective to accomplish that. That means the upper end of the table.

You don’t actually need to calculate DR yourself to do this, but if you want to you will need an analog step tablet such as the Stouffer TP 4x5. B&S sometimes has them in stock or you can get it direct from Stouffer. The inexpensive strips such as the T2115 are not ideal for this since the steps are too small to read accurately with most spectros. Once you have the 21-step values, either density or L*, you plot it and evaluate it to find the Exposure Scale which equals the Density Range required in the negative for the particular process you are using and all the variables including paper. In many cases (but not all), the variables don’t vary so much that you actually need to calculate it for every situation.

One thing that I and some others who come from the film world have noticed is that the ISO standards that we apply when doing this for camera negatives don’t necessarily apply for digital negatives. This is because the linearization process essentially takes the characteristic curve of the film out of the equation. I have come to the conclusion, though, that it is still useful to apply some correction to the paper characteristic curve to adjust for toe and shoulder (highlight and shadow) compression that is inherent in all photographic printing processes.

After saying all that, here’s what it comes down to – assuming your previously stated 40 drop total, not including additives like Tween

  • A+B method: Use 18+2 or 19+1 (this is a little more or less than the 11+1 I used in my 12 drop schedule)

  • If keeping the chlorate separate, add 1 drop of 0.6% potassium chlorate to 20 drops of plain FO. The hardest part of using this method will be making such a dilute solution of chlorate. If you were making 100ml you would be using 0.6 gm which will require a scale that can accurately read to 2 decimal places. But 100ml is way more than you need since you will be using only 1 drop at a time. Even 25ml (0.15gm) will probably last a very long time. If you are going to be scaling up in size, it might be worthwhile to make a set of serial dilutions like I do with Na2 starting with a 20 or 10% solution which is much easier to weigh. If I didn’t have enough Na2 to last the rest of my life — a little goes a very long way — I would have already done this myself! And if I ever want or need to print with a mix of Pt and Pd I will do it.

Hope that answers your question.