Platinum/palladium outside negative is a beautiful black. Blacks in photo are not...?

[LFman]

Hello all!

I tried my first two platinum (Na2)/palladium prints a couple of days ago. After 30 mins in a plate burner, the excess coating on the paper was a nice, rich black, but the black areas in the print (from under the (in-camera) 4x5 neg) were not. The negative is fairly dense. If it helps, I could probably scan the results in a couple of days.

Does this mean I should use more Na2, maybe make a digital neg with appropriate curves, expose for longer, or perhaps a combination? Could my old UV tubes be too weak from age?

For reference: 6 drops of palladium, 6 drops of ferric oxalate #1, 2 drops of Na2 platinum (5%), coated with glass rod over almost an 8x10 area on Arches watercolour cotton paper. Exposed in an old plate burner (maybe from the 50s!) for 30 mins (after a 10min exposure was way too light). Normal developing with ammonium citrate for 2 mins, quick wash, clearing with EDTA for 5 mins and another wash. All chemistry is about a year old from B&S, but only just opened/mixed a couple of days ago.

Many thanks for your wonderful insights!

 

[jp498]

Is by chance tmax 100? 100 has a UV blocking layer.

 

[lecarp]

You may have over-exposed the film.

 

[deisenlord]

If you have a nice black in the film rebate area but not in the print you simply have to much density in the shadows that your expecting to be black. Na2 is simply going to shorten the scale, not effect the shadows. As lecarp indicates you may have overexposed those areas. You could try increasing your print exposure. Printing platinum from in-camera negatives means you need find your personal film EI and development time so as to match the scale of the platinum emulsion.

I'd drop back to some film testing.

Just as a side note, density isn't your friend, it will just make for very long printing times. What you need, at least compared to a negative for silver, is a higher contrast negative.

 

[TheFlyingCamera]

You might also be getting a bit of reversal of tone from the long exposures. As a general rule I try to keep my printing times under 20 minutes. If you're having issues at 30, your negs are probably too dense.

 

[gzinsel]

base + fog. there is always a certain amount of fog with development. ALWAYS. there is the density of the base, so B +F is ubiquitous in line of work. Imo, your neg is problem, not the chemistry. Of course I am saying with out a shred of "real" proof, however, your chemistry sounds right. I have found out that If I do not have proper exposure ( shadow detail) and proper development( highlight detail. I re-shoot. Its too much B.S. with farmers reducer, etc. or selenium toning the neg. If you don't get it right. Make an inner neg. see unblinking eyes web site, article "less is more".

 

[LFman]

Thanks for all the kind responses!

I just did some testing. I printed a digital step wedge on pictorico using a cheap inkjet printer. First two prints took 30 mins to get any density into the 80% grey region (inspected during exposure) but after developing, the black areas (0% grey, and outside the negative area, i.e. no film covering it) were disappointingly light. I thought it might be the amount of chemistry used for the coating (7 drops for an area about 50% bigger than a 4x5).

I then coated an 8x10-sized area with 12 drops of palladium, 12 drops of ferric oxalate #1, and 2 drops of Na2. It only took 20 mins to get some density in the 80% grey box. After developing, the black was slightly darker. I also did a test strip with the original in-camera negative I had trouble with before, and it was very light... so yes... the negative was too dense. I will fix that with a digital negative.

Ideally, I'd like my black to be blacker, and a faster developing time. Does anyone know a good way to do this? Is more chemistry the answer, or perhaps a stronger Na2 concentration (mine is only 5%)?

Thanks

 

[sly]

What about trying a new batch of ferric oxalate? It goes off. I keep mine in the fridge, when I'm not using it, and discard when it is 6 months old.

 

[Vaughn]

...Ideally, I'd like my black to be blacker, and a faster developing time. Does anyone know a good way to do this? Is more chemistry the answer, or perhaps a stronger Na2 concentration (mine is only 5%)?

I assume you meant shorter exposure time.

I use a lot more chemistry for an 8x10 -- about 20 drops ferric + 20 drops pt/pd. I get a very rich black. It might also decrease your exposure time a little.

Below: 8x10 platinum/palladium print (no contrast agent used). The image looks a little more contrasty on my screen than in reality.

 

[Andrew O'Neill]

Try acidifying the paper. When I make kallitypes, I soak the paper (Rising Stonehenge) in a 1% solution of Sulfamic Acid (tile cleaner from hardware store). Then wash the paper thoroughly in running water. Some people use a stronger acid bath, but 1% works for me. You should notice much darker blacks. You may have to adjust your exposure time. I had to cut mine by half a stop.

 

[pschwart]

I like Andrew's suggestion. If you are using a buffered paper and don't acid soak, you are in for trouble.
My base exposure is about 13 minutes using BL tubes. Typical dmax is 1.45 but can get > 1.5 with care.

 

[Mainecoonmaniac]

Never printed platinum prints before, but that's a gorgeous print Vaughn!

 

[thomnola]

You mention covering an 8x10 sheet with chemistry but are only using a 4x5 negative. That seems to be a waste of precious metals! And, perhaps, the chemistry is spread too thin with only a 6 drop count?

 

[LFman]

Thanks for the tip about ferric oxalate going off. I didn't know - I will order some new stuff and test out my old stock by adding a bit more.

 

[LFman]

I cut the paper in half after coating so I can expose two negs I started adding more chemistry, too.

 

[LFman]

I am using Arches Watercolour paper. Not sure if it is buffered. I've heard people use Arches Platine, but it's not in stock anywhere here and I haven't got around to ordering online. I'll have to do some digging to see if the watercolour paper is bufffered.

 

[TheFlyingCamera]

Try Bergger COT-320 - it is specially formulated for alt process printing. It's about the easiest paper to print pt/pd on I've ever found. Platine has its own issues. Do some searching here on APUG for discussions of paper for pt/pd - there are lots of them here with a lot of really good information.

 

[LFman]

Thank you for the Berger tip. Will certainly get some.

I also just did some more testing. I increased the ferric oxalate by 50% and exposure time is now down to 15 mins with the full step wedge nicely exposed. After developing, the blacks were a lot better, but the effect of fog was very evident comparing the 100% black under the pictorico step wedge (0% box) and the black edges which didn't get any pictorico covering them.

I'll experiment with some Berger and some new ferric oxalate

 

[Loris Medici]

See (there was a url link here which no longer exists) about how to make (otherwise unsuitable) papers comply to the needs of iron processes including pt/pd...

Regards,
Loris.

 

[LFman]

THanks everyone for your help. I got some Bergger COT-320 at TheFlyingCamera's suggestion and I now have nice, rich blacks. Now my only problem is getting a better printer... my current cheap Epson can't print solid blacks (there are very thin lines it misses) despite print head alignment/cleaning etc.

Thank you so much!

 

[Loris Medici]

A note: IME, sulfamic acid treated Fabriano Artistico Extra White will give you richer blacks than what you can get with COT 320, and more apparent dynamic range due to the brighter paper base.