Jack,
"Subsequent research demonstrated that calcium or magnesium bicarbonates were fa
r safer to use with paper, and the use of sodium bicarbonate in paper conservati
on went quietly away."
 
I can't think of any exceptions to the case that Group I elements are too reacti
ve for use in paper conservation when they can be easily replaced by an alkaline
 earth Group II element.  As you probably recall, once upon a time  the conserva
tion literature debated the merits of the Na vs. Ca chlorinated compounds for bl
eaching, and while that discussion is now long dead, the echoes of Na cellulosic
 swelling remain in my ears.  Also in this context, I believe the ability to rem
ove transition group elements like iron and copper is better with a Ca or Mg bic
arbonate.
 
Coming out in JAIC soon will be another article in which Ca vs. Mg solutions use
d in aqueous light bleaching are considered quantitatively.  Let's discuss it wh
en you get a chace to see it.
 
Jim Druzik