JAIC 1990, Volume 29, Number 2, Article 2 (pp. 117 to 131)
JAIC online
Journal of the American Institute for Conservation
JAIC 1990, Volume 29, Number 2, Article 2 (pp. 117 to 131)

CHEMICAL WATERMARKING OF PAPER

STEPHANIE WATKINS



3 MICROSCOPIC EXAMINATION

SOME OF the objectives of an early chemical watermark patent were to form watermarks “involving the adequate displacement of entrained air,” “replacing air in a paper product with a material having an index of refraction similar to that of cellulose,” and “by impregnation thereof to replace entrapped air in a localized area” (Vaurio 1963). To determine whether the watermarked materials interact with the paper as the patent states, the papers were examined under magnification.

Scanning electron microscope (SEM) images were taken of the cross-section of the GE watermarked paper. Two magnifications, 500 and 1000, were used on both the plain paper and the chemically watermarked areas. The images produced are disappointing, as the material is indiscernible from the fibers. However, it is apparent that the chemicals “swell the fibers somewhat and close up the sheet” (figs. 1–4)(Block 1989).

Fig. 1. SEM cross-section, paper area, GE sample, 500 (1989)

Fig. 2. SEM cross-section, paper area, GE sample, 1000 (1989)

Fig. 3. SEM cross-section, chemical watermark area, GE sample, 500 (1989)

Fig. 4. SEM cross-section, chemical watermark area, GE sample, 1000 (1989)


Copyright 1990 American Institute for Conservation of Historic and Artistic Works