Pinacyanol (synthetic dye)
From Kook Science
Pinacyanol is a synthetic blue dye derived from coal tar that was used for sensitizing photographic plates, manufactured in the early twentieth century by the dye works of Meister, Lucius & Brüning at Höchst (near Frankfurt), Germany. It became associated with auric research thanks to the experiments of Oscar Bagnall, who continued from Walter J. Kilner's earlier research and reported success in substituting dicyanin dye with pinacyanol in his own experiments, leading him to speculate that other blue or violet coloured dyes should have the same effect.
In Dyestuffs & Coal-Tar Products (1915), the authors — Beacall, Martin, et. al. — relate that the pinacyanol is quinoline dye of the isocyanine type, reporting it is "obtained by treating quinaldinium salts with formaldehyde, followed by alkali."
- Walters, Jr., Francis M.; Davis, Raymond (1922), Pinacyanol, "Studies in Color Sensitive Photographic Plates and Methods of Sensitizing by Bathing", Scientific Papers of the Bureau of Standards (Washington, D.C.: U.S. Dept. of Commerce) 17 (422): 360-366, https://babel.hathitrust.org/cgi/pt?id=mdp.39015010797002;view=1up;seq=472
- Bagnall, Oscar (1937), "Apparatus and How to Use It", The Origins and Properties of the Human Aura, London: Kegan Paul, Trench, Trubner, p. 46, "It is, of course, possible — even probable — that dyes other than dicyanin have the same effect upon the nerves of the retina — I have got good results from pinacyanol. The necessary qualification is that it should be of a blue or a violet colour; one that will transmit the shorter-wave lengths of the spectrum. In fact, it should bring the object slightly nearer to the eye."
- Beacall, Thomas; Sand, H. Julius; Martin, Geoffrey; Challenger, F. (1915), "Photographic Chemicals: Quinoline Dyes", Dyestuffs & Coal-Tar Products: Their Chemistry, Manufacture and Application; including Chapters on Modern Inks, Photographic Chemicals, Synthetic Drugs, Sweetening Chemicals, and Other Products Derived from Coal Tar, London: C. Lockwood & Son, p. 139, https://babel.hathitrust.org/cgi/pt?id=uc1.$b71225&view=1up&seq=157