Re: Paper negatives

[Katharine Thayer <kthayer@pacifier.com>]

On Oct 12, 2008, at 5:47 AM, Laura Valentino wrote:
> Katharine: I'll try that with the sodium bisulfite (I got some in a  
> kit I ordered once). But I rather like the warm tone on the  
> successful print, so I'll leave it alone, as long as it doesn't  
> hurt anything (like cause the paper to deteriorate or something).

Laura, there's long been a caution repeated in many sources that  
dichromate stain should be removed or it will cause the paper to  
deteriorate; some sources insist that even if there's no visible  
stain, the print should be "cleared" after drying to eliminate any  
unseen dichomate products in the print that can eventually destroy  
the paper.  But that seems to be just one of those things that gum  
printers believe that may or not be true, and is probably based in  
misconception.   Since we don't actually know what dichromate stain  
is, chemically, any statement  about its eventual effect on paper,  
pro or con, should be taken with some skepticism.  At any rate, I  
think most gum printers nowdays consider clearing optional (I  
certainly do, and uncleared gum prints two decades old, at least,  
show no signs of deterioration).  Hope that's useful,
Katharine