RE: Trivia time: room temperature solubility of platinic acid (re-send)

Cor,

It is pretty simple for straight palladium printing, and also works
with kallitype. You just add small amount of dichromate to the
developer. The more you add the greater will be the contrast of the
print. Useful amounts range from about 1ml of a 5% dichromate
solution per liter of developer up to perhaps 16ml per liter. This
allows you to print negatives with DR of up to 1.8 or 1.9 to as low
as perhaps 1.1. However, at the higher amounts prints start to get a
grainy look. However, I am printing palladium these days almost
exclusively with digital negatives so I make these to a high DR so
that I use very small amounts of dichromate in the developer, say no
more than about 2ml of the 5% solution per liter. This makes the
print a lot easier to clear and hardly affects the exposure scale of
the paper. Some sources say the dichromate method does not work with
the citrate developers, but it works just fine at my house with
sodium citrate.

Na2 is a better method if you need to print negatives with a
relatively low DR, say negatives you exposed and developed for silver
printing.

Sandy

>Sandy,
>
>You wrote..
>
>>
>> Most of my printing is done with digital negatives which have a DR of
>> about 1.8 and my preferred method of palladium printing is with
>> dichromate contrast control, not Na2. However, I have made quite a
>> number of prints with the Na2 method and the result has always been as
>
>> I describe.
>>
>> Sandy
>
>..could you elaborate a bit on "my preferred method of palladium
>printing is with dichromate contrast control, not Na2"...
>
>Thanks,
>
>Cor
Received on Mon Dec 12 19:13:06 2005