PT /PD Print Problems

[tomharrison]

Hi All

I was wondering if I could pick your brains and ask you a question about a persistent problem I'm having with my PT/PD printing?

I keep noticing a strange light speckling occurring every so often. In this example it's present to the left of the lamppost, pretty much in the center of the print...

I'm using Arches Platine paper, brush coated (hake) with a 7062 PT/PD mix. The developer is Potassium Oxalate (at room temp.) with Potassium Dichromate added for contrast control.

The paper doesn't appear to have been abraded during coating and I'm pretty sure it's not a chemical stain. Could it be a defect in the paper itself?

Any suggestions would be gratefully received!

Many thanks in advance,
Tom.

 

[PVia]

Tom...

It could be a paper problem. Platine has been known to be inconsistent in the past.

It could also be a coating problem; I'm not fond of hake brushes for pt/pd, much prefer a good watercolor flat wash brush.

Also, is it possible that something touched the paper on that spot before coating. A hand will transfer body oil easily.

BTW, what's a 7062 mixture?

 

[Davec101]

Hi Tom

Did you try that tween i gave you?

 

[nze]

Ok

Arches platine as COt 320 need to brush a little longer compare to other paper. If not some of chemical will stay on the paper ( not in) and will wash in the developer. You can use as suggest by Dave some twenn 5 you can dilute @1%) and just add a drop to your mix. Too much tween and solution wil get deep in the paper.
It is a quite commmon problem with Arches platine