I printed some test negatives as platinum prints and had a friend read the maximum density of the blacks. D Max topped out at 1.3. Is this as good as one can get with a platinum print given the materials I use? If not, what changes would I have to make to get a deeper blacks?
For an 8 x 10 print, the drop count is as follows:
12 drops Ferric Oxalate
10 drops Ferric Oxalate with Potassium chlorate
8 drops Potassium Chloroplatinate
16 drops Sodium Chloropallidate
Paper is Cranes Platinotype
Developer is Ammonium Citrate
If you are a devotee of pt/pd, then you know these are all from Bostick & Sullivan.
I don't personally have/use a densitometer but according to Arentz's book a pt/pd print can achieve a Dmax of 1.5 (compared to 2.0 for 'silver). He states that a Dmax of 1.35 for pt/pd will produce a 'convincing black'. Hope this helps.
Yeah, thats about right with cranes platinotype. !.3, 1.4 is about the highest D max I have ever been able to get. But his should not bother you, I have not seen What Clay put in the portfolio, but if you look at my print, you see there is what Arentz calls "convincing" blacks.
Dont worry about getting very, very black tones, just that they "look" black. This is one of the most difficult parts about pt printing.
Thanks for the reassurance. When the portfolio gets back to Mexico, I hope I can "convince" you with my blacks. 8)
BTW here is a tip Clay gave me, if you add a drop of PVA to the solution you can get a little bit better blacks.
Platinotype has always been somewhat stubborn in producing deep rich blacks.The PVA and quick warm forced air drying immediately after coating seem to help. The best papers I have seen in this regard are double coated Platine and double coated Mars Vellum or Clearprint Vellum. I have gotten Dmax's of 1.5 with both of these papers. Add an ivory black gum-over layer for a brief exposure and you can do even better. I've never busted 1.35 with platinotype. But as Dick Arentz says, it's enough to convince most viewers that don't have scientific measuring devices in hand.
PVA - Polyvinyl Alcohol or Polyvinyl Acetate, or something else?
Polyvinyl alcohol - available from B and S. I put about 1 drops per 1ml of sensitizer/metal solution whenever I use platinotype, Uno or Lenox, which all seem to be more 'spongy' and absorbent than Platine and Whatman's, which are both heavily body-sized papers.
My working theory is that I need to keep the solution near the surface on the absorbent papers by using the PVA sizing and quick warm air drying. On the other hand, I allow it time to absorb into the heavily sized papers such as Platine and Whatman's by just letting them dry with ambient temperature and a little moving air.