Re: Tricolour gum and PDN
Separate the positive into RGB channels. Convert the RGB negs back into RGB because they are greyscale now. Then invert, and then put your curve adjustment layer on top of each separate negative, and the PDN color layer on top of that. I don't know if this is what you are already doing but it may help if not.
BTW, according to Sam Wang diluting cyanotype sensitizer makes it a bit slower and more contrasty but not lighter. I actually mix my cyanotype at 2A:1B, even. Be sure you are printing the cyano layer with the R neg, too?
One interesting thing I notice--gum over cyanotype, being that it is acidic, tends to make the cyanotype nice and blue. You will notice that where the gum does not cover the cyano it washes to a paler blue gray, but underneath the gum it is good and dark.
It is a PITA when the cyano goes too dark on you, isn't it--you can't scrape it off.
I'm sure this goes without saying that the cyanotype curve is different than the gum curves?
When you figure it out I hope you post your results to the list.
----- Original Message ----- From: "Henry Rattle" <firstname.lastname@example.org>
To: "alt photo process" <email@example.com>
Sent: Saturday, September 02, 2006 2:35 PM
Subject: Tricolour gum and PDN
I wonder if anyone who has used PDN for tricolour gum can help?