Re:PT/PD

Pietro DeFilippi (pi.defilippi@agora.stm.it)
Fri, 22 Nov 1996 22:05:14 GMT

Terry
Thanks for your replay

>>At the moment I'm working in the classical way :
>>**PAPER =3D Poggi( by Arches available only in Rome) Arches=
>> Aquarelle/Platine
>
>Try Fabriano Artistico satina from Milano.

I will. But I was just trying to awoid sizing,I don't know why but i hate
sizing. I have seen you use deionised ossein by Croda colloids.What is it
exactly ? Sounds to be a sort of animal glue. (so i can try to find the
equivalent in Italy).
-----------------
>**COATING = double by brush (i have also built an acrilic rod but only=
>used
>Size first with a 1 % size and you will need only one coat.
>>**CONTRAST AGENT = potassium clorate in the sensitizer
>
>Vary the proportions of platinum to palladium to give contrast control .
>Potassium chlorate gives too much risk of ugly grain.

I know I can achive contrast control through the percentage of PT/PD but I
dont want to loose the chance to control the color of the print, so i think
I have to use another contrast agent , may be Sodium Dichromate and K Oxalate?
-----------------

>>**DEVELOPER = mostly ammonium 20C.[77F.] i'm trying to get neutral
>blacks
>The classic developer is potassium oxalate which tends to give improved
>gradation and highlight and shadow detail.
>>**FIX: =Kodak hipo clear. i used HCL but yellow everywhere at any
>percentage.
>
>Use three baths of EDTA disodium salt 5 % solution

What is wrong whit Hipo ?(I dont want to be nasty , I just want to
understand why chose one product and not another one) at the moment Hipo
seems to work well for me but if you have a specific reason to avoid it, the
information is welcome.
-----------------
>>**NEGATIVES =original neg. enlarged onto 4x5 Kodak Tech.Pan,developed in=
>> low
>>concentration paper developer. positive enlarged onto N31P developed in Agfa
>>G5, for final neg.(i started developing in HC110 but i had a very hight=
>> fb+f).
>
>If you are working at 5 x 4, FP4 developed in PQ Universal at 1 : 9 for
around
>two minutes, or Amidol, will give you negatives that will give you platinum
>prints that will outshine the results you are getting now.

For negative you mean in camera negative or what?
I'm starting from already existing negatives, so i have to get through
positive and then final big size negative. I chosed Tech.Pan for the
positive to get no grain,(if properly treated can a be long scale film too)
and for the final neg (i want to rich prints bigger than 8x10) i must use
Agfa N31P or Agfa GO21OP ,because i dont think i can find any other film so big.
About Amidol are you referring to the Wenston's paper developer or the
Amidol wather bath negative developer?
[formula # 6 from darkroom cook book] I have no experience of Amidol and
unfortunately i have also the problem that everithing i use for no silver
process cames from abroad , i mean to find the right product it is not
easy. By the way if you have an address of a British supplier I'll
appreciate.
What is PQ universal? whic brand?
---------------
>> i have seen few PT/PD prints really terrific.
>
>This is really important. Many people think that their platinum prints are
good
>because they made them. Many modern platinum printers have never seen a good
>platinum print and so have no criterion by which to judge their work.
>
>>I have 2 problems:
>>-A- lack of sharpness. I will experiment with paper, because i have mostly
>>used POGGI paper that is very textured,if it will not succed i will try a
>>different printing frame.
>
>The texture is your main problem. The Fabriano gives beautifully sharp
prints as
>does Waterford
I do agree . I understand the smoother is the paper the best is the
sharpness but dont forghet the sensual pleasure of a heavy and textured
paper , i was just trying to find a way in between the sharpness and the
pleasure of a sensual paper. For sharpness what about vaacum printing
frame? where is it from and whic brand is Waterford?
-----------------
>> Extension grays too short(blacks too closed / whites too short / Dmax
>is ok)
>
>You are using the wrong film and the wrong developer.
>
>Try this way and forget the contrast controls.

Thanks for your suggestions Pietro

__________Pietro De Filippi__________
_______pi.defilippi@agora.stm.it_______