Any Na2 users out there?

[Alan9940]

A quick question for anyone who uses Na2 in their palladium printing...

What is the effect, if any, of print size to the number of Na2 drops in the mix? For example, my normal mix for a 5x7" print is: 8 drops Palladium + 8 drops FO + 1 drop Na2 (5%) + 1 drop Tween. If I were to make, say, an 8x12" print would I need 2 or more drops Na2 to maintain the contrast characteristic of my 5x7" print? How about doing a 4x5"? Would I use 1 drop of 2.5% Na2? Or, does the drop(s) of Na2 remain constant regardless of print size?

Thanks for any insight provided.

 

[fgorga]

For consistent results, you need to keep the final concentration of all components as constant as possible. Thus, you definitely want to adjust the amount of Pt you add when you adjust the total volume. Thus you are correct that you would want to use 1 drop of a more dilute solution of the Pt.

I say "constant as possible" above because when counting drops you sometime need to make a choice... do I round up or down.

In any case, here is how I would adjust the drop counts you gave for a 5x7 print to both 4x5 and 8x10.

I doubt that the minor differences in composition as you adjust will make a difference. Only a trial will tell for sure.

 

[Alan9940]

Thank you, Frank, for your help and the great chart! I, too, figured that applying a ratio to my "base" drop count would probably be the way to go. It's nice to see that someone else thinks the same. I will follow your advice and see where it leads me.