Determine the basic exposure for palladium printing
The attached test strip was the one that I made for determining the basic exposure for palladium printing. I used a blank sheet of Pictorico Ultra Premium OHP Transparency Film to cover part of the coated area on Bergger COT-320. And It turned out that the area covered by the film would never reach the same density as the uncovered part, even if I had increased the exposure time up to 6 minutes. Its density was in gradual increase in brown, could not even reach dark brown, while the uncoverd part seemed to have reached its Dmax within 2 minutes.
And for coating the paper, the suggestions I found on the net are telling that 6 drops of Ferric Oxalate plus 6 drops of Palladium solution would be sufficient for a 4X5 -inch image. I didn't realize that it was not sufficient until it turned out to be. What's the common practice in this situation? Let it dry down and give a second coating?
Sorry for the naive questions as I'm all new to the process.
Thanks much in advance for any kind reply!
Based on what I use for an 8x10 (~22 drops ferric/22 drops pt/pd on Cot320) , the amount you used seems sufficient.
What light source are you using? 6 minutes does not seem long to me...my exposures are much longer with my LF negatives (more like 30 minutes) which tend to be very robust, but it is difficult to compare camera and digital negatives.
I will let those more experienced with digital negs answer. Good luck in your explorations!
At least with LF landscape, a bad day of photography can still be a good day of exercise.
Check this out, just scroll down until you see all the titles for platinum and palladium printing.
Sudek buy a couple of 31 step tablets (from Stouffer - the T3110 variant - or PDN, I personally find the latter is better for our specific requirements...) and cover half of the tablet with the transparency material so that each step is half covered, and test again until you get at least two steps merged under the tablet + transparency, your standard exposure will be 1/3 stop less than what is needed to merge two steps under the tablet + transparency. (Because the test material UV density is about 1/3 stop ...) Standard Pictorico needs at least 2/3 stop more exposure IME. Therefore if you're getting black in 6 minutes w/o the negative material, you'll need *at least* 6 x ( 2 ^ (2 / 3)) ~= 9,5 minutes with Pictorico. (Probably a little more, I think Ultra is more opaque to UV...)
Last edited by Loris Medici; 09-15-2013 at 04:45 PM. Click to view previous post history.
Some papers and brushes are more absorbent than others. I usually use the same amount as you when I want to coat a 4x5 without going all the way to the edge, which is my usual way of coating paper. I'm using a 2" hake brush and Arches hot press. I add another drop of each if I want to coat all the way to the edge.
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Vaughn: I used 8 black light tubes (30 watts each) and the distance between the tubes and the exposure plane is about 6 inches.
Rick: Thanks much for the link!
Loris: Thanks so much for the detail instruction!
WetMogwai: Thanks much for sharing the experience. I'll look for a hake brush and have a try.
Sorry for the late reply. I replied twice since the day before yesterday. But I don't know why it couldn't get approved to be posted. Not sure if it can be approved this time.
I've been trying to do more testing before resorting to step tablets and thus kept testing for longer exposure time, while shortenning the distance between the tubes and the print.
Finally I shortened the distance to about 1.5 inches and exposed for 2.5 hours (see the attached, the right side covered by Pictorico Ultra Premium OHP Transparency Film). The result that it's still far from being dark is driving me crazy.
Can anyone give me some advice? Would a step tablet make a difference? I really don't know what to do next. Longer time would lead to solarization, as what the four-hour strip showed. And isn't it unreasonable to expose a print for several hours?
Thanks and sorry for my ugly brush strokes
PS: The paper is Bergger COT320, prewet for ten seconds before coating. a Hake brush. 6 drops FO+6 drops of palladium solution for an image area of 4X5 inches.
Off-hand, it does not look like your paper is clearing very well, but it could be a number of other factors in the image - it may or may not be part of what you are seeing. A question: how old is your FeOx? I have been told it is good for six months, but only keep my FeOx three or four weeks.
I do not prewet. I use sunlight and Pictorico and cannot relate to times with a UV box.
Hi sudek, what kind of lightsource do you use? Do you practice any other UVA sensitive process? (You can try with another process and see if it's exposing slow too - if yes, it's the lightsource / not chemistry.) Have you tried another paper? (Cheap Masa paper is very iron-process-friendly, try with another paper too, in order to rule out any problems with paper...) Pt/pd and hours of exposure doesn't seem right to me, especially so for materials like Pictorico... If you're Europe based see for Philips tubes ending with -05 or /05 suffix, these are perfect for UVA sensitive processes. (Output peaks between 360-370nm) Tube codes ending with -05-R or /05-R ending have in-tube reflectors; even better...
P.S. Just for sake of comparison; my standart printing time with POP Pd under UVA tubes and 2mm glass is around 6-8 minutes, and (because of self masking) POP Pd is usually a little slower than develop out Pd.
P.S.2. I don't understand what you mean by pre-wetting the paper? IME, COT 320 doesn't need any kind of special treatment...
You're right, it was not cleared enough. I just cleared this strip in Citrid Acid for five minutes. The result exhausted my patience to go through the complete procedure. Usually I would use Citrid Acid for the first bath, and EDTA+Sodium Sulfite for the second and third bath. Each bath five minutes respectively. But the problem is that the yellow stain would still be obvious even though I went them through the complete procedure.
The FeOx has been three months old since I received it from B&S. I know it's a bit old. But it still seems to work well in the uncovered part.
Thanks so much for the kind suggestion :-)
For pre-wetting the paper, I mean humidify the paper by holding it in the mist from a humidifier for few seconds. It's said to be helpful for reaching a deeper black, or so I have heard. :P
And there's one thing I can't understand. Should there be anything wrong with the paper, the solution, the tubes or the glasses, the part that was not covered by the Pictorico film shouldn't have reached its Dmax within 2 minutes in my first strip, and in totally dark too in the following strips with longer exposure time except for the four-hour one.