Architectural drawings

I have been looking seriously for information describing
conservation of ink on linen architectural and engineering drawings.
The few items in the distlist archives suggest that the coating is
potato starch but there is nothing that I can find in the literature
that talks about the processes used in creating the coated
substrate. Can anyone direct me to the written sources for this
information?

Randolph Stilson
CAPNW

                                  ***
                  Conservation DistList Instance 11:70
                Distributed: Thursday, February 12, 1998
                       Message Id: cdl-11-70-007
                                  ***