Metal Contamination
Stephen R. Harrison (102053.1342@CompuServe.COM)
02 Aug 96 22:40:46 EDT
I am having a problem with, I assume, metal contanimation of some sort in my
Pt./Pd. Printing It is especially noticeable in skies and appears under a 30
power microscope as as a small black pit in the center ( literally the size of
the point of a pin) with black radiation emminating from it. There may be only 2
or 3 of these on any given 7x17 inch print and are very small. Question:
Because of such contaminates, does all developer water need to be distilled ? Do
people generally filter the developer after each use or after the days use to
eliminate any possible contaminates that may have crept in? Is a regular coffer
paper filter sufficient to remove such contaminates from the developer? Can the
products of the Pt reaction ( Ferrous Oxalate ) that remain in the developer
after the print is removed contaminate the developer for the next print? I
notice for example after a days printing, a residue of small black particulate
matter at the bottom of my glass developer beaker. Does this have any bearing on
the problem ? Does the residue at the bottom of the Pt and Pd bottle influence
this sort of problem. There is nothing worse than a beautiful sky with a tiny
volcanic crater in it! Any suggestions. Stephen Harrison