NOTES

. 1 Joyce Plesters, “Cross-sections and Chemical Analysis of Paint Samples,” in Studies in Conservation 2, No.3, April, 1956, pp. 110–157, Microchemical tests used included hydrochloric acid which bleaches ultramarine blue, and sodium hydroxide which discolors Prussian blue to a dark orange yellow.

NOTES

. 2 Rutherford J. Gettens and George L. Stout, Painting materials, A Short Encyclopedia (New York, 1966) pp. 149–151.

NOTES

. 3 Gettens and Stout, p. 151.

NOTES

. 4 Penelope H. Batcheler, Historic Structure Report, Old North Church, (National park Service, Denver Service Center, 1981) pp. 193–194.

NOTES

. 5 Walter C. McCrone, Lucy B. McCrone, and John Gustav Delly, Polarized light Microscopy (Ann Arbor: Ann Arbor Science Publishers Inc., 1979). p. 35. A pseudo-opaque white appears to be opaque because the light that is transmitted though the thicker agglomerated particles is bent and does not enter the objective lens.

NOTES

. 6 Gettens and Stout, p. 147.

NOTES

. 7 McCrone, McCrone and Delly, p. 169. The refractive index determination using dispersion staining was carried out by Dr. Walter C. McCone in the conservation lab at N.Y.U.

NOTES

. 8 Natural Ultramarine, Forbes collection, 7.01.13.

NOTES

. 9 Prussian Blue, Forbes Collection, Azzuri de Prerlino and Bibbiena.

NOTES

. 10 Gettens and Stout, p. 148b.

NOTES

. 11 Prussian blue, Slide reference set of 1982 from The McCrone Research Institute.

NOTES

. 12 Plesters. HC1 and NaOH microchemical tests, p. 137.

NOTES

. 13 Electron microprobe analysis preformed by Walter C. McCrone and McCrone Associates. 1984.

NOTES

. 14 Penelope Hartshorne (Batcheler). Log of Restoration, Independence Hall, Tower Stair Hall, 1956–57.

NOTES

. 15 The size of the particle agglomerates visible in the paint film do not necessarly indicate an early or late date of manufacture. I have seen very large Prussian blue agglomerates in early 19th century blue paint films from buildings in Tennessee and in Texas.

NOTES

. 16 Charcoal Black (Forbes: 2.01.7) and Lamp Black, McCrone Research Institute.

NOTES

. 17 Private communication with Dr. Robert Feller. 1986.

NOTES

. 18 Walter C. McCrone, written correspondence to the author: “Even with the same process, there can be differences in the product, especially particle size. This would be due to variations in temperature and time.” 1987.