I post this here after Walker suggestion.
I’ve run and closing up the a final cureve andd icc profile to fit Pd-Ox printing together with my Epson R3000 and Pictorio Ultra. I’ve been using Arches Platinum, the new as they call it now. I like the paper except the put a sticker on the paper in one corner close to the water mark and this damage the surface when I remove it. The work with Pd have progress better then my I expected with both Pd and PiezoDN tool.
This week I recieved a package of the recent apprais Hahnemühl Platinum Rag paper. This gave me today a very blotchy result. I tried both side if I’d missunderstand that the smooth side shouldn’t be the side to be coated. More or less the same results.
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My chemicals. I bought ready mixed from Bostick and Sullivan. I’ve used #1 (ferric oxalate) and #3 Palladium, from the bottle. The are mixed by them this month, so I consider them as fresh. Also when I used them today with Arches Platinum and the results were as smooth as has beem last week.
I coat the mixture (1:1) with a moddler brush the was pre-wetted. Let papers dry as recommended.
Expose in my unit (UV-fluorescent light). After this I developed in 25% potassium oxalate for 2 minutes. The blotchiness was now seen. After this step short rinse and treatment in EDTA and final rinse.
Walker comment me if I use Tween20, but not so far.
//Christer
This paper really requires the use of Tween 20 or another surfactant like PhotoFlo.
There is no need to rinse between developer and clearing bath. Best practice is to use 3 successive trays of clearing bath. The first does most of the work. After several prints when it has turned orange, dump it, slide the 2nd and 3rd over to 1st and 2nd positions, and make a fresh 3rd bath. When you start to see color in the 2nd bath it is time to rotate. The 3rd bath should never show color.
For many papers, EDTA alone is not sufficient - Arches Platine has long been one of those, I don’t know about the new Hahnemuhle. I add citric acid and sodium sulfite to the EDTA. One tablespoon of each per liter of water, maybe less of the sulfite.
Possible solutions:
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add tween 20 into the sensitizer, probably 1 drop will be enough.
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add 1 to 2 drops of traditional platinum solution into the sensitizer in order to avoid solarization.
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do humidify the paper a bit…but i don’t know whether your paper is too dry or not. (just my thoughts)
Cheers…and happy printing.
Harris
Thank you for your proposal. I’ve Tween 20 at home. If I understand you just a small amount is needed.
I’ll try this later this week.
Second concerning solarization. When I detrimine the basic exposure I saw the tendency for longer exposures that the reflection density was reduced after having a maximun. I can handle this, but as aslo is discussed the humdity and temperature can unexpected change this.
During the experiments I’ve had a temperature 20-21C and a RH between 40-55%. Do you think this variation is to large? I set up a box and keep the papers with help of a saturated salt keeping it constant. In fact I do so when I keep my carbon tissue in carbon/pigment printing process.
//CT
I use 1 drop per ml of solution for most papers. It’s not that critical. 1ml is approximately 16 drops. I use 2ml to coat for an 8x10-ish print. 1ml FO + 1ml Pd + 2 drops Tween20. I think your temp and RH are good, though I aim a little higher with the humidity. My space is usually around 60% (50-65% range) if my hygrometer can be trusted. The humidification box is a good idea. Wish I had room for one. What salt do you use and what humidity?
In that case I’ve to dilute it to 10%.
Thanks Keith
I found an unanswered Q. I use a saturated solution of sodium bromide. This gives a RH of 55-58% of a practical temperature range.
//CT
Thank you Keith.
With Tween 20 you mean drops from concentrated Twen 20, ie not diluted?
//CT
I have always obtained my Tween 20 from B&S as a 10% solution. If that is what you have, then yes, undiluted.
If you have a stronger stock solution, then first dilute to 10%.
