Mary Virginia Orna

The Chemical History of Color

Introduction: Colors, Natural and Synthetic, in the Ancient World.- Discovery of the Physics of Color.- The Chemical Causes of Color.- Colorant Usage from Antiquity to the Perkin Era.- Beyond Perkin.- Major Analytical Techniques Based on Color: Volumetric Analysis Chromatography Spectroscopy Color Measurement.- Color on the Biological and Biochemical Front.- Finale: Color in Foods, Photochemistry, Photoluminescence, Pharmaceuticals, Fireworks, Fun and the Future.

The visible and infrared microspectroscopic characterization of organic red pigments removed from three medieval Byzantine manuscripts

Abstract Infrared and visible microspectroscopy has been used to characterize microscopic red paint fragments removed from Byzantine illuminated manuscripts dated 10–13th century, ad . Spectral evidence indicates the presence of carminic acid lakes in two of the manuscripts studied and the use of a mixture of vermilion and an anthraquinone lake in a third.

Discovery of the Physics of Color

Anyone who has shared the company of three-year old children for an afternoon will recognize the conversation. Everything you say is challenged immediately with their favorite word—why? Newly arrived in the world and fascinated by all they see, three-year olds want to know the why of everything. They live in a world of mystery, wonder, and possibility—where magic is real and reality is magic. As we explore the discovery of the physics of color origin and perception, put yourself in the place of the three-year old who always wants to know why. Or put yourself in the place of the discoverers themselves who must have been filled with awe at what they learned and communicated to the world for the first time.

Finale: Color in Foods, Photochemistry, Photoluminescence, Pharmaceuticals, Fireworks, Fun, and the Future

This final chapter will alliteratively pick up many topics that fell outside the trajectory traced by the history–chemistry—color interface in the previous seven chapters. We will see how colored additives affected the food quality of the past and, by extension, how color has affected, and continues to influence, so many other aspects of our daily lives.

Color on the Biological and Biochemical Front

One of the many things that the German dye companies excelled at was seeing the long-range and global picture and acting upon it. They went very large-scale on virtually every front, utilizing all the weapons that science and technology had to offer. They found that doing so enabled them to synthesize two important natural colorants, indigo and alizarin, thus eliminating the industry’s dependence on natural products and imports—the dye industry could now not only be self-sufficient, but could use the know-how generated in these key syntheses to make many other derivatives. In addition to setting up large laboratories that employed hundreds of chemists, they built libraries that had subscriptions to virtually every scholarly science journal in the Western world, they established dedicated bureaus to patent discoveries, and they virtually “wrote the book” on abstracting services by having these offices work around the clock and not only in the area of chemistry, but in every other domain that might afford them related knowledge—biology, the emerging area of biochemistry, pharmaceuticals, photography, and explosives.

Colorant Usage from Antiquity to the Perkin Era

Images of butterflies, cats, dogs, fairies, ghosts, witches, wizards… kids of all ages love having their faces painted in these fanciful ways. They stand in a long tradition. From ancient times, body and face paints have been used for cosmetic, ceremonial, military, and religious reasons. There is reliable archaeological evidence that human beings have painted faces and bodies since the very beginning. The ancient Picts used red ochre, as well as woad (an indigo-bearing native plant). Julius Caesar remarked in book five of De Bello Gallico, “All Britons paint themselves with woad, which grows wild and produces a blue dye. This gives them a terrifying appearance in battle”.

Discoveries Among the Rare Earths

When Johan Gadolin (1760–1852) took up the challenge of examining a small sample of a strange mineral found in the feldspar mine near the little Swedish village of Ytterby in 1788, little did he realize that he would set in motion a search that would last for over a century. The sample, named “ytterbite” by Lieutenant Carl Axel Arrhenius (1757–1824), its discoverer, could not have fallen into more skilled hands. Gadolin, at that point in his career climbing the academic ladder at the Royal Academy in Abo (present day Turku), Finland, had studied chemistry under Torbern Bergman (1735–84) at Uppsala and excelled in analytical chemistry.

Entrepreneurship, Innovation, Patents and Products

There is no question that Carl Auer von Welsbach was a supreme innovator—his fertile imagination was able to take ordinary observations, made time and again by others, and transform them into useful inventions, as evidenced by the three great examples described in the previous chapters. That his entrepreneurial abilities were called forth by the necessity of promoting his inventions were obvious, but need to be analyzed.

Legacy of Carl Auer Von Welsbach

On the morning of the first of September, 1928, a distinguished contingent of gentlemen descended on the quiet village of Treibach-Althofen and made their way up to the heights of Welsbach Castle to pay their respects to its proprietor on the occasion of his 70th birthday. Perhaps nothing else could demonstrate the esteem and high regard in which Auer von Welsbach was held than the credentials of this honorable group of well-wishers from every part of the world: official representatives of government, industry, scholarly and scientific societies, universities and polytechnic institutes.

Didymium’s Twilight and Two New “Stars”

Long experience in dealing with the rare earth elements and the difficulty of separating them one from the other made chemists aware of the pitfalls of claiming that they had succeeded in producing an unequivocally pure compound. Furthermore, the claimed discoveries turned out to be a tangled web of errors mixed with grains of truth as investigators tried to go over old ground, that is, to take another look at minerals once pronounced to be completely separated and analyzed.