I’d be grateful if anyone with experience of using the Malde Ware Method 2 PtPd chemicals on Hahnemuhle Platinum Rag paper can help me resolve a coating issue.
I have a lot of experience with the Bostick & Sullivan Pt/Pd chemicals and get excellent results on Hahnemule Platinum Rag, although I add 10% of the sensitiser volume of 20% Tween 20 to achieve smooth coatings.
With the Malde Ware chemicals on Weston Diploma Parchment paper, the addition of the same amount of Tween 20 again produces excellent results. However, the attached image shows the blotchiness they give me on the Hahnemuhle paper and the example shown had 10% of the sensitiser volume of 20% Tween 20 added as well as 10% volume of Glycerin 10% solution.
My workflow is as follows:
Humidify paper over hot water for 1 minute.
Rod coat paper. Wait a few minutes then dry with warm air to achieve paper humidity of 18%. (Paper humidity of 14% gives a very warm print, 27% gives a neutral one).
UV exposure in a vacuum unit for 350 seconds.
Rehumidify over water for 5 minutes, then process in EDTA Na4, Na Sulphite, EDTA Na4, wash
The mylar film separating the coated paper and negative do not show any reaction product sticking to it so the blotchiness is entirely within the paper.
I don’t understand why and if the Malde Ware chemicals should behave in this way and I imagine that adding yet more Tween and Glycerine will not help.
I’d welcome any suggestions. (Don’t worry that the target print has the darks and whites reversed. I correct that in a spreadsheet.)
Many thanks
William Hume
