Coating different papers with different processes, my observations:
I started off with the traditional process and found that I could not get into solution the ferric oxalate. Had a wonderful conversation with the Mrs. at Bostick and Sullivan. She said it should readily dissolve contradicting Dick Arentz claims in his book on printing Platinum. I bought the ferric oxalate from Art Craft Chemicals. Perhaps there are different grades. Three hours at 150 degrees Fahrenheit on a stirrer with the correct volume. You think it would dissolve?!?
The purpose was to find the optimum printing times and ink densities for digital negatives using theMike Ware process where you set the print time to find the optimum black, then the ink density at that time to find your optimum white. I refer to the “Maxium Optical Density” or MOD which is found in the bowels of your Epson printing screens. I used the matte black ultra chrome inks on an Epson 4880 with Arista II OHP film. This is probably made by Pictorico. Note, I have only worked withpalladium so far. My light source is a tubular high intensity discharge lamp which may be an arc lamp; nevertheless, it’s not your typical uv box. This is one bright 3 inch bulb I inherited from an old printing process.
The traditional palladium process on Arches Platine needed 27 units of light (compared to 60 – 120 for my PMK negs) with an MOD of -9. Treated Artistico Farbriano traditional White required the same time and MOD to produce identical density ranges with a slightly lighter DMax but a very different look.
The Mike Ware Process palladium on an old stock of Cranes Crest Natural White required 37 units of light with an MOD of -6, or it required more ink for the same density ranges. Given that it is a printing out process, that makes sense. The Aristico produced the same density ranges given the same time and MOD; however, in this case the DMAX was considerably lighter.
Three side observations:
- Washing the ware pd print before immersing in the diNa EDTA produces less mottling at least with this old Cranes stock.
- When using syringes, I found pulling the plunger up a bit to allow an air bubble before you pull the solution will expel all the solution when pushing out than annoyingly leaving a remnant in the tip.
- My brown bottles evaporate solution. (I am open to suggestions for better 25, 50 & 100ml large mouth brown bottles. The evaporation causes the proportions to be off in the working solution as well as producing a precipitate. I read somewhere that too much of the oxalate or too much of the metal causes problems such as mottling.
- Printing out is ever so different than the traditional develop out process.
- The print out process requires more ink than the traditional process.
- The print out process requires more UV light than the traditional process.
- PMK negatives require a lot more light than ink negatives.
- Hot Pressing the treated Artistico paper makes for easier coating.
- Ironically, coating with rods, Artistico is more difficult to get the solution even on the first pass, than the other papers, but requires more passes–strange.
- Printing step wedges isn’t very rewarding!
- Predicting a good exposure on the traditional process is an art.
- Exchanging papers (Artistico Trad Wht with Arches Platine) uses same MOD and time for identical density ranges.
- I still have to do the same process for printing with platinum on various papers. But first I need to look into the next step, getting a decent digital negative printed out.