NOTES

1. Culligan deionizing system-anion/cation exchange columns, two prefilters and a neutralizing column filled with calcium carbonate chips. Normal pH of this water without the addition of calcium hydroxide solution is approximately 7.4 as measured by the E.M. Merck indicator papers.

2. If possible, it is desirable to choose a purer grade enzyme over the crude grades. Of the two bacillus subtilis amylases available from Sigma, there is Type IIIA cited in the literature, which is a crude grade and, although free of foreign extenders, contains extraneous protein material, and Type IIA. Type IIA has been 4X crystallized. Alpha Amylase's ability to hydrolyze starch is measured in activity units. One unit will liberate 1 mg maltose from starch in 3 minutes at pH 6.9 and 20�C. While Type IIIA has approximately 73 units/mg protein, the refined Type IIA has a specific activity of approximately 1,350 units/mg of protein. Reaction time is often much quicker with this preparation and it requires only 1/10; the concentration as the crude grade.

3. The paper expanded approximately �″ on all sides; but an exact measurement was not taken.

4. Each quadrant remained in the tension system for approximately seven hours. The inks were unaffected by this system. One concern had been the possibility of blanching caused by moisture trapped between the ink layer and Mylar. Tests with smaller expendable posters on equally thin paper, indicated that all moisture could be successfully withdrawn from the poster's verso.

ACKNOWLEDGEMENTS

IWOULD LIKE TO THANK my fellow conservators in the Hirshhorn Museum conservation laboratory for generously allowing me the extra space necessary for a project this size. Susan Lake deserves special thanks for her valuable assistance with this treatment.

REFERENCES

Brown, Robert K. and Reinhold, Susan. The Poster Art of A.M. Cassandre. E.P. Dutton, New York, 1979.

The Museum of Modern Art. Posters by Cassandre (catalogue of the exhibition with forward by Ernestine M. Fnatl). New York, 1936.

Barnicoat, John. A Concise History of Posters. Oxford University Press, New York and Toronto, 1972.

Delhaye, Jean. Art Deco Posters and Graphics. Rizzoli International Publications, Inc., New York, 1977.

Segal, Judith and Cooper, David. “The Use of Enzymes to Release Adhesives.” The Paper Conservator, 2 (1977).

Gratten, David W., St.Hilaire, Johanne, Burgess, Helen, and McCawley, J. Clifford. “The Characterization of Enzymes for Use in Paper Conservation.” The Cambridge Conference Preprints, 1980.

Correspondence and telephone conversations with Dr. William Jacoby, an enzymologist at the National Institutes of Health, Bethseda, Maryland.