Dear Keith
AS promised, please find attached photo with the formula i get from a book called “The Platinum Printing Workshop” by Ian Leake. please review and give me some comments…YES…you are absolutely right 5 to 10 seconds means nothing to alternative printing.
AND…please also find the problem of my print currently using Hahnemuhle paper… you will see the fog around the 129 patches print out…
I am going to do a test tonight…minimize the lighting condition…use a newly produced potassium oxalate and disodium EDTA…and i will tell you the results later.
Harris
Dear Keith
I just did another 129 patches print using freshly made potassium oxalate, disodium EDTA, Hypo…Tetrasodium EDTA…but the results are the same as before…
just minor difference… then check my old print out and discovered that almost all my prints have “slight fog” around the edge of the coated area.
YES…it affects my highlights and also my linearization. of coz I won’t see it when it comes to real prints (i mean the fog edges), but since it affect the highlights…i am very unhappy about it…
So…any possible solution on this???
Do you think the problem arise because of the following?
-
The 5000Watts UV exposure unit (too strong?)
-
my sensitizing solution??? i mixed it myself…all Fe, Pd, Pt…
-
My tungsten lightbulb…? (should be ok)…
-
tween 20…10%? should not be i freshly made it…
Harris
You need to use a small amount of NA-2.
Also, the next release will include an updated 7900-9900 “bullet-proof” master curve with an Optical density over 3.5 and a UV density over 6.
best,
Walker
Here is a beta curve built for 5000k plate-makers and POP (print out process) palladium printing on the 7900-9900
best
Walker
Dear Keith and Walker
thank you very much for your reply. I guess i have no choice but have to use some Na2 as sensitizer…!! I never use it before even though i have it in my cabinet…
Keith…NOW i know what you are talking about in the previous Forum Messages… Originally, i thought PiezoDN can 100% control the tone and contrast which make me think i do not need to use any Na2.
I will do all linearization process AGAIN by using some Na2 for both Berggar and Hahnemuhle paper…let’s see whether the issue can be resolved…
I am sure both of you know it is NOT interesting to REDO linearization coz it takes a lot of time…but i will keep up with it and achieve good results…
THANKS WALKER AND KEITH!
Harris
Dear Walker
I have tried to use Na2 already…YES…the fog gone away!!
Question: if i use 80Pd20Pt…but my platinum solution is traditional solution and NOT Na2…can i use the Na2 if i discovered a little bit of fog??? Otherwise…what should i do?
Should i use Ferric Oxalate contrast agent???
Harris
Dear Walker and Keith
Please find attached the fine edge D-max test paper…
Walker as you said for palladium…i only used 1 drop of 5% Na2 on a 8x10 paper…and the fog goes away…thank you!
Please refer to attached photo : )
Please answer the previous post question if you can.
Harris
Dear Keith
Thank you so much for your answers… it seems that if i want to do platinum palladium prints…i have no choice but have to use FO-A and FO-B method…thank you…
I will try to mix some different ratio of FO-A and FO-B and see how much i will need in order to avoid fogging.
i just finish my test and home 15 minutes ago…finally…after another D-max test with 300 seconds as base…and 20 seconds increment…finally i choose 340 seconds as the standard exposure time, and the linearization curve seems ok to me…at least it is not a U-shape curve and already quite close to the “standard line” as provided by PiezoDN smoother tool.
The second paper is Hahnemuhle paper…with 2 drops of tween 20. same proportion like yesterday but it seems it is not as good as yesterday test…maybe because of my coating techniques… 
I am going to do the second linearization and ICC tomorrow…lets see how it goes…
MANY MANY THANKS KEITH!!!
Harris
Dear Keith
I almost finished my linearization by using Na2…as you may expect…the Na2 maybe too strong that wash out my highlights… i am using 5% solution now.
Is it ok to use distill water to dilute the 5% to 2.5% or 1.25%…?? Just use distill water right?
please advice.
Harris
Yes, 5% is too strong for this image size and solution volume. 1.25% should be sufficient.
Here is what I recommend to make 2.5% and 1.25% Na2 solutions. You will need 2 small bottles ~ 30ml. I am assuming you are starting with a 25ml bottle of 5% Na2. You may want to alter the amounts if you are starting with less.
- Draw 12ml of 5% Na2 and transfer it to an empty bottle.
- Add 12ml distilled water.
- You now have 24ml of 2.5% Na2. (And 15ml of 5% remaining.)
- Transfer 8ml of the 2.5% Na2 to the other empty bottle.
- Add 8ml distilled water.
- You now have 16ml of 1.25% Na2, 16ml of 2.5%, and 15ml of 5%.
Dear All
It seems the use of Na2 blown up some of my highlight area of the 129 patches…according to the CGATs data/curve from the smoother tool… even though i did another linearization in the hope that the “highlight washout” may disappear…
It seems the 5% solution of Na2 from B&S is too strong for my case…so…just want to as k should i dilute the current 5% solution in 2.5% just by pouring more distill water into the solution…5% 10 ml to add another 10ml to make the solution into 2.5%… ?
Anyone knows whether the solution from B&S is stock solution or working solution??? is that ok to just dilute it by using distill water?
Harris
Dear Keith
I just discovered that you’ve covered how to dilute the 20% Na2 in your website… many thanks!!!
PS> but can i dilute my existing 5% Na2 from B&S?
Harris
Dear Keith
Thank you very much for your answers!! THANKS A MILLION!!
I guess i can do a better job on 129 patches linearization tomorrow
I will use my existing 10ml 5% Na2 to do the dilution as above first, and order some from B&S tomorrow.
Cheers
Harris
Harris - Please see my previous message(s).
It is both stock solution and working solution depending on the strength you need which varies depending on the print size and solution volume that you are using.
All of the following are equivalent in terms of the strength of Na2 to volume of solution:
- 1 drop of 0.6125% Na2 in 1ml of solution (0.5ml FO + 0.5ml Pd)
- 1 drop of 1.25% Na2 in 2ml of solution (1ml FO + 1ml Pd)
- 1 drop of 2.5% Na2 in 4ml of solution (2ml FO + 2ml Pd)
- 1 drop of 5% Na2 in 8ml of solution (4ml FO + 4ml Pd)
With digital negatives we want to use the minimum amount that keeps the highlight free of fog without increasing contrast. My tests, repeated many times over many years always with the same result, have shown that this minimum effective amount of Na2 actually extends the tonal scale by 0.05 - 0.1 density over not using any Na2. This is counterintuitive, we would expect no Na2 to have a slightly longer tonal scale, but my test have shown otherwise. This is why I prefer to uses it even if it is not necessary to prevent fog. It is a personal choice in my case. In any case, all of these personal process choices must be decided upon before linearizing because most if not all of them have some effect on the linearization. If you change something in your processing chances are good that you will need to relinearize.
I just saw your message where you say you have 10ml of 5% Na2. So still follow my directions on how to make the other dilutions in my previous message but start by transfering 5ml of your 5% Na2 to an empty bottle and add 5ml distilled water to make 10ml of 2.5%. Then transfer 3ml of that to another empty bottle and add an equal amount of distilled water to make 1.25%.
Hope this all makes sense.
Dear Keith
Thank you again for your answers!!
According to your reply about Na2 and how to dilute it, please correct me if i am wrong.
The conclusion is: I need to use 'just" enough “strength” of Na2 solution for “avoiding fog” for my prints…but the strength of the Na2 counts on 2 factors, 1, the size of the print (according to the table in your website)…2, the contrasty level of the negative. Which means i cannot use , for example, 2 drops of 1.25% Na2 solution to replace 1 drop of 2.5% solution…the “strength” of the Na2 must be specific to print size and negative contrary level…is that correct? : )
Harris
With digital negatives, we have the luxury of tailoring them to our process. Generally speaking, most Pt/Pd printers would agree that the longer the scale the better, so we aim to use the minimum amount of restrainer if we use any at all. On my chart, this means look at the top row only. The rest of the chart is for working with original film negatives where try as I might to get them perfect for the process via exposure and development controls, I don’t always hit the target (and sometimes I’m way off) so the full range of contrast control is very useful.
You certainly can use 2 drops of 1.25% in place of 1 drop of 2.5%. If you look on the chart at the higher contrast levels and larger volumes you will see multiple drops of 20% listed. If you want to use only a working solution of 1.25% and use multiple drops for volumes larger than 2ml there is no reason not to. You would simply use 2 drops for 4ml, 3 drops for 6ml, 4 drops for 8ml, etc.
Here are a couple of graphs to illustrate what I was talking about earlier regarding the difference between printing with no Na2 and using the minimum effective amount. The graphs come from the old BTZS Plotter software by Phil Davis. The x-axis is NA2 %, the y-axis is resulting Exposure Scale in the print. The source data is readings from prints of a Stouffer 21-step using the full range of contrast control available with Na2. (Other restrainers, such as potassium chlorate in Ferric Oxalte-B or sodium dichromate added to potassium oxalate developer, behave in a similar fashion.) Notice that the first graph uses an IDmax (maximum Image Density) of 90%. This is an old standard from Kodak (and other film manufacturers) to compensate for the shouldering off of shadow separation as commercial silver paper approaches black. It is very relevant for printing Pt/Pd from large-format film negatives as well. With digital negatives, however, we can compensate via linearization for the shadow compression that is a characteristic of the printing process, so it makes more sense in my opinion to use the entire scale, hence the second graph has IDmax set at 100%.
As for the 0.3% and 0.6% Na2 levels, since the Stoufer 21-step is 4x5 inches, I use 0.25ml FO + 0.25ml Pd + 1 drop Na2 for these tests. At that small of a coating volume I needed the lower dilutions. I rarely use them for anything else unless making really small prints. The 0.3% here is equivalent to using 1.25% in a 2ml coating volume.
[attachment file=1621]
[attachment file=1622]
Dear Keith and Walker
By using 1.25% of Na2 for 129 patches test (i did both 2.5% and 1.25% for the 129 patches area)…i got this…it seems it is good right? Keith, do you think i need to do further linearization??? this is only the first one…it seems the highlight is a bit “down” and the over the tone goes down just a little bit.
Thank you very much for your (both Walker and Keith) teaching!!
Keith …please comment : )
Harris
That looks very good. I agree with your analysis and think it would be a good idea to do a second linearization.
Na2 (Sodium hexachloroplatinate) is not compatible with the standard platinum solution (Potassium tetrachloroplatinate). If you use them together you will get a grungy precipitate (not sure if this is the correct term technically) visible in the lighter tones. Use Na2 only with palladium.
When using Na2 to eliminate fog, you want to use the minimum amount necessary to accomplish that task without actually increasing contrast. I have tested this extensively, and refer you to the chart posted on my website. If you are working from Bostick & Sullivan’s 20% stock solution of Na2, here is how to make a set of serial dilutions. The dilutions I use most frequently are 1.25%, 2.5%, and 5%, depending on the volume needed for the image size and paper I am using.
- Example: for an image size / paper combination that requires 2ml of solution, use 1ml FO + 1ml Pd + 1 drop 1.25% Na2 + 2 drops Tween 20 or PhotoFlo
If you wish to use the standard platinum solution is your mix, maybe to get a less warm more neutral image hue, you will need to use a different method of "contrast control". The traditional A:B ratio method uses a minute amount of potassium chlorate in the Ferric Oxalate B sensitizer. Traditionally, with original large format film negatives of varying density range, we would vary the ratio of the plain (A) and modified (B) Ferric Oxalates. With this method I used a 12 drop system of measuring where 12 A + 0 B is used for the contrastiest negatives (longer exposure scale print), and 0 A + 12 B is for the softest negatives (shorten exposure scale print).
- Example: to get a result similar to the above example, use 11 drops FO-A + 1 drop FO-B + 2 drops Pt + 10 drops Pd + 2 drops Tween or PF.
Note: The 2 examples are probably not the exact same volume since drop size can vary, but it is fairly close. There is nothing that says you must use a 12 drop system - use whatever is convenient for you. But if you increase it you, will need to verify that 1 drop of B is sufficient to prevent fog since you are using relatively less of it.
In the first of the attached images, it looks to me like your exposure time should be closer to 360 than to 450, maybe around 400, especially since you are starting to see solarization on the uncovered part at 450.
What is the second image showing? It doesn’t reach black at all, and doesn’t look very smooth either. Is that HPtR without Tween?
