Fax paper

...
Cheryl Jackson of the Australian National Archives did a simple research
project reported in Abbey Newsletter v. 13., no. 8, 12/89. The 2 papers
she tested were poor-quality wood pulp sized with alum rosin, but
calcium carbonate fillers raised the pH to about 8.5.  She seems to
indicate that this is representative of the medium.  The "image" layer
is a heat-activated "colorless dye" with a "color-forming agent"
suspended in a binder (no formulae or chemical identifiers given).  Heat
triggers visible color somehow.  Most important of Jackson's findings
seem to be that hot water and most reagents turn the image layer black,
and some remove it all together. Simple washing and single-layer drying
seemed to cause no problems, but the paper blocks in stacks.   Images
fade in high humidity, and high temperature causes predictable results,
but UV doesn't selectively obscure the image -- just makes everything
darker.  She notes discoloration was worst where there were
fingerprints.

Jackson reports that the manufacturer of Kanzaki thermal paper doesn't
estimate life expectancy of more than five years, even under "optimal"
conditions.

Karen Motylewski
Northeast Document Conservation Center

                                  ***
                   Conservation DistList Instance 7:5
                  Distributed: Saturday, June 19, 1993
                        Message Id: cdl-7-5-009
                                  ***