7 FINAL CONCLUSIONS

With respect to the color, opacity, and gloss properties of tracing papers subjected to the aging, solvents, and humidification and flattening conditions used in this study, the greatest change in color occurred with aging, the greatest change in opacity occurred with solvents, and the greatest change in gloss occurred following humidification and flattening. Water was the solvent that caused the greatest overall change in properties. The natural tracing paper was the paper most affected by aging; the prepared tracing paper was the paper most affected by solvents; and the imitation parchment was the paper most affected by humidification and flattening.

The preliminary findings of this research must be considered tentative for the following reasons: (1) vegetable parchment paper samples have not been completely analyzed and tested; (2) none of the papers have been aged after treatment to determine the long-term effects of treatment; (3) no solvent tests have been performed on aged papers; (4) techniques of microtomed cross sectioning and UV microscopy, both promising for characterization of papers before and after treatment, are still being developed, modified, and evaluated; (5) a database of FTIR reflectance spectra for thick coatings, transmission spectra on samples pressed on a diamond cell for medium coatings, and extraction spectroscopy for thin coatings is still being developed; (6) comparative studies of multiple papers, such as additional samples of vellum papers, have not been completed; (7) replication of the measurements of dimensional and planar changes has not been undertaken; and (8) there are many other solvents, application techniques, and humidification and flattening techniques (such as using a drying board or friction drying) that might be used successfully with tracing papers but were not tested in this project.

ACKNOWLEDGEMENTS

The authors would like to acknowledge the help of CAL staff and interns including Melanie Feathers, Mel Wachowiak, Ron Cunningham, and Jennifer Beers, and the many other consultants and conservation interns associated with various parts of this project over the years for their generous donation of materials, time, and expertise.