It is commonly used as a paper to paper adhesive in the treatment of
works of art on paper.  Some have also experiment with it for the water
soluble coating on colorfield paintings.  It has also had many other
adhesive uses in Conservation.  I believe the big advantage was that it
was both water soluble and could be put into organic solvents as well.
It has side groups (never used it have now forgotten) which make it
questionable for permanence (my opinion) compared to straight
"methylized" cellulose (methyl cellulose), which works very well, but
only soluble in water.

Timothy Vitale
Preservation Associates
831-684-2731