RE: copper prints

[Richsul Sullivan <richsul@earthlink.net>]

Bruce,

Neither am I a chemist but here are two things to try:

Several baths of dilute hydrochloric acid 2%.

Develop in Dektol or HC110 for 3 minutes and wash thoroughly.

The first is a clearing bath for engraving black toner, the second is for my
platinum and palladium print gold toner. 

Both are cheap and the materials are readily available so maybe worth a try.
The HCL may wipe out the copper but the Dektol might reduce out any wet
nasties causing your problem.

--Dick Sullivan



-----Original Message-----
From: Bruce [mailto:steelbar@shaw.ca] 
Sent: Saturday, January 17, 2009 4:52 PM
To: alt-photo-process-l@sask.usask.ca
Subject: 

Hi All
So I have now made several attempts at making Cuprotype prints using  
Jim Patterson's formula that Christina posted in October. I have had  
varied results and a near disaster(that's another story). The  
resulting colour tone is a wonderful terra cotta red when I used BFK  
paper and a not quite, but still good, colder tone when I used  
Plantine. The dmax is good when it is wet but is too low when it  
dries. I have not tried to double coat or adding ammonium dichromate  
to bring that up but I have another problems that are more pressing.  
The problem is that the print is getting an overall light blue stain 
(some times not so light) after as short a period of 3 days and  as  
long as 3 months.   It looks fine after it has been dried and than  
after a period of time it quickly goes blue. It tends to be  
relatively even over the white paper surface, front and back. In  
order to stop this problem I increased the clearing bath from a total  
of 4 min to 8 min with 3 baths, always with fresh chemistry. I also  
went from the 3 changes of wash baths as recommended to 30 minute  
wash time. One of the prints that I did I washed for 2 hours and it  
still had a light blue tinge.

So my questions are
1) Is anyone else trying this process and have they experience and  
similar problems?

2) Could this be the reason that this process never caught on, that  
it is not stable?

3) I am not a chemist but can some one explain to me in layman's  
terms how this process works. It is not like other photo processes,  
with this you coat the paper than develop that paper until the image  
disappears, than you "clear" it with the developer that has been  
diluted(what's that going to do). The blank paper is than put into a  
strong bath of chemicals which is normally used as a bleach and a  
photograph appears and than you wash it in water. Is that magic or what.

Thanks for any help
Cheers
Bruce