By , Ph.D. The ChemQuest Group
Over the past two or three decades, there has been a well-publicized amount of consolidation within the paint and coatings industry that has often trudged behind the demise of large customers such as Sears, Roebuck and Co. (1889-2018).
Sears-branded paint accounted for 43% of DeSoto Paint Co. coatings, and losing this large customer was the beginning of the end. One of my personal favorite house paints of all time was the Sears Ultralight Latex Interior House Paint, which—with almost imperceptible drops of color added to a gallon of white satin paint—provided a subtle, color-shifting visage to any room. Hints of color danced on the walls, depending on the day’s weather—sunny or cloudy—and even upon the type of light bulbs used in lamps and chandeliers. Unfortunately, both DeSoto and Sears are now distant memories, swallowed up by other companies or private equity groups, their products visible in aging family photographs.
While the Sears/DeSoto saga is a recent example of obsolescence, the coatings world has been reinventing itself for millennia. Pigments, which are the cornerstone of paint, have come and gone since prehistoric times. The first pigments were ground earth or clay held together by liquid or fat. Surprisingly, many of those colors have survived to this day, as seen by the cave paintings often highlighted in National Geographic. Modern synthetic pigments are laboratory chemistry experiments designed to replicate the colors used by Renaissance masters—while eliminating some of the less-desirable poisonous effects.
Resins and binders that surrounded pigments have also evolved. The Renaissance masters used egg yolk and oil in their paintings and frescoes encased in plaster while multifaceted polymer families are used in modern paints. Modern biobased paints are trying to return to the plant and animal derivatives of bygone centuries but are hampered by the need for large scale production, not generally needed in earlier times.
The most fascinating changes have taken place in the world of pigments. Pigments are defined as colored, black, white, or fluorescent particulate organic or inorganic solids, which are insoluble in, and essentially physically and chemically unaffected by, the vehicle or substrate in which they are incorporated.1 The first pigments are believed to be the minerals limonite and hematite (red ochre, yellow ochre, and umber), charcoal (carbon black), burned bones (bone black), and ground calcite (white, lime white, or chalk).
Ancient Egyptians, Romans, and Greeks developed inorganic iron oxide pigments, again making red ochre, yellow ochre, and umber. “Lead white” and ‘lead red,” which were made through chemical reactions in lead vessels, were colors favored by artists because of the brilliance and depth they added to make a painting shimmer. Vermillion is still a highly favored color, even though it was originally made with mercury sulfide.2
While red ochre, yellow ochre, and umber can still be made today in the traditional way, pigments containing lead, mercury, and sulfide are generally no longer available.
Paleolithic cave paintings started with red and black. Over time, the color palette expanded. The Lascaux cave paintings in France, accidentally discovered by four boys in 1940, were still vivid and clear-probably protected by the cave’s darkness and its secluded area. These paintings, which researchers believe were drawn during the Ice Age, used a basic palette of red, yellow, black, brown, and white to create vivid, vibrant depictions of animals, scenery, and life.
In 1948, the owner of the land above the caves opened the door to tourists, and more than 400,000 people visited annually. The visitors’ collective breath, the warm air intruding into the cold caves, and the installation of electric lights caused these vivid colors, once preserved for thousands of years, to fade away into invisibility in only 20 years3 —a stark reminder of arf s vulnerability and impermanence.
As Victoria Finaly wrote in The Brilliant History of Color in Art, “And this is another element of the history of colors in art: they are there and then they go. They do not stay the same, and when you look at a painting, you’re also, in a tiny way, changing it.”3
Another example of aiding and abetting obsolescence in the coatings world.
Pigments were not used only for aesthetic depictions. The Tiwi (meaning “We, the only people”) population on the Tiwi Islands used color primarily from natural ochre pigments to ensure that marriages did not occur between people that were too closely related. Children were identified as a “color” at a very young age. Red (sun), black (stone), white (pandanus bush), and yellow (mullet fish) identities determined who could marry (or not). Reds could marry yellows or whites, but not reds or blacks. Whites and yellows could marry blacks. In this culture, color was forever synonymous with destiny and even the afterworld as depicted on funeral poles. These color norms are still in place, but are being challenged by the younger generation.4
Continue reading in the March-April digital issue of CoatingsTech