"Lilies #1" ~ Platinum/Palladium Print (Na2) ~ New Portfolio
The Cochise Stronghold portfolio of palladium prints is finished, with eleven prints printed, and more that can be. This new portfolio is really a continuation of the current palladium portfolio, an addition to the palladium prints. As I've noted more than once, the portfolios are printed simultaneously writing a book on the process. These two portfolios are two sections of the same book on printing in palladium. The Na2 process, or 'double sodium', for using a sodium based platinum, is palladium printing with a couple drops of platinum in a diluted % solution.
Two things happen when adding the sodium based platinum; sodium chloroplatanate, to the palladium solution. First, it replaces the need for the ferric oxalate #2 solution in traditional platinum/palladium printing, which controls the contrast of the print image. That oxalate #2 solution is a chelated form of ferric oxalate, with a small amount of potassium chlorate added, which is the contrast controller. The downside of using the oxalate #2 is simply the more you use of it proportionatly with the ferric oxalate #1, the more reticulation of the image. Reticulation is same same as "grain" in the negative, upon the print image.
The second thing that happens with the % of platinum solution added is seen in the lower tonal ranges; zone 1 up to zone 3, where shadows are deepened, with zone 1 black reach dMax black. This is because the platinum stops the bronzing that takes place in palladium printing. The simple of it being the blacks get printed in first, and longest, with a buildup of the oxidation during the reduction process of the metallic salts. The blacks in palladium printing stop at some point in the printing and begin to show a lightening of the deeper blacks, showing up as "bronzing". The added platinum stops this, pushing the blacks into dMax, or 'maximum' black.
It is the middle tones that show the steely blue gray platinum look one expects of platinum. With a very shortened tonal range, with deep blacks and brilliant whites, what ends up being seen are both, with little to nor middle tones, or very little, as in the image below. This image was printed last year as a Kallitype, toned in palladium, to warm it. This round I went the other direction. Cool tones, deep blacks. The platinum solution I use is 2.5% platinum (DHr20). This is the percent solution used if the negatives being used have sufficient contrast to print well in palladium. For softer negatives the solution can be mixed to 5% or 10% which would increase the image contrast quite a bit.
Platinum/Palladium Print ~ Na2
"Lilies #1" ~ 8x10