U of S | Mailing List Archive | alt-photo-process-l | RE: Mike Ware's POP Pt./Pd. Pt

RE: Mike Ware's POP Pt./Pd. Pt

The difference in tone between printing a negative with a DR of 1.8 and one of 1.2, after adding the necessary amount of Na2 for the lower contrast negative, can be quite significant. But to be frank, most of my negatives are processed for DR of 1.8 and can be printed with very small amounts of either Na2 or dichromate.

BTW, did I understand you to say that you use Disodum EDTA as developer for both DOP and POP Pt./Pd?


At 9:24 AM -0600 11/11/06, Eric Neilsen wrote:
Sandy, I think for users of Na2/Platinic Acid for contrast control would
only see a significant color shift if they are only using PD or very very
small amounts of PT to begin with. I have not noticed any color shift using
it as a contrast method, but then again much of my work has at least 40% PT
in the coating solution already.

However, just about any contrast control will some effect on color compared
to other methods; it is a matter of degree as the amount of contrast agent
is added to the solution.

And for those in the UK or Europe, you need not look for Na2, but simply ask
you metal supplier such as Engelhard for platinic acid.

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
Skype ejprinter
 -----Original Message-----
 From: Sandy King [mailto:sanking@clemson.edu]
 Sent: Saturday, November 11, 2006 7:38 AM
 To: alt-photo-process-l@usask.ca
 Subject: RE: Mike Ware's POP Pt./Pd. Pt

 I know what Na2 is and have used it as a contrast agent. I just did
 not know that it was called Platinum 6. Several people I know have
 adopted this method of contrast control and it does have some
 advantages. However, I have continued to use dichromate for straight
 palladium work because the use of Na2 causes a shift in color, i.e.
 the more you add the more neutral the color becomes, whereas with
 dichromate you get the same color over a wide contrast range. At
 least that is my experience. I believe you suggested in an earlier
 message that the use of dichromates causes a change in color, but I
 sure have not found that to be the case with pure palladium.


 At 11:46 AM +0100 11/11/06, Witho Worms wrote:
 >See the Bostick&Sullivan site: Na2- A New Contrast Agent - An interesting
 >salt of platinum allows for wide ranging contrast control in the
 >platinum/palladium process. Great news for all platinum printers, read
 >(http://www.bostick-sullivan.com/techart.php) You will there find some
 >interesting information on POP too.
 >-----Oorspronkelijk bericht-----
 >Van: Sandy King [mailto:sanking@clemson.edu]
 >Verzonden: zaterdag 11 november 2006 1:39
 >Aan: alt-photo-process-l@usask.ca
 >Onderwerp: RE: Mike Ware's POP Pt./Pd. Pt
 >What is Platinum 6?
 >At 6:14 PM +0100 11/10/06, Witho Worms wrote:
 >>I would recommend using Platinum 6 as a contrast agent for DOP. I can
 >>very well. Dichromate is very effective in POP but affects printing
 >>-----Oorspronkelijk bericht-----