• Michael Skalka

Let's Raise a Glass to Naphthol Red

Summary: An unusual relationship exists between the brewing industry and the invention of a host of synthetic organic pigments in the azo family. This is the story of the relationship between the birth of the wide variety of azo dyes that were later transformed into pigments used today. This Syntax of Color essay will examine the pigment PR 170, Naphthol Red, one of the many hues of red that artists can place on their palette.



I knew that someday my hobby of wine making and the study of pigments would eventually intersect. A repeated theme is stated when anyone embarks on learning the process of taking a sugar ladened fruit and converting into alcohol is that fermentation is a biological-chemical reaction of vast complexity. Grapes mingled with yeast and time will change the sugar in the fruit to alcohol and emit carbon dioxide. But the chemical process does not stop there. Natural and accidental contaminants can turn what could have been a good wine into a bad one if a sneaky little bacterium like acetobacter is allowed to thrive in the yeast infused grape juice. Without proper sanitation of equipment, a host of harmful critters can cause havoc that can spoil a batch of grape juice. Wine is a complex chemical mixture that when made with care can produce all the olfactory and palette pleasing sensations one can expect from it.


It appears the same notion about how beer is produced created the environment that spawned the creation of azo dyes. In comparison to wine, I liken beer as a change of ingredients and methods that has similarities to the steps wine makers employ. I think of beer and a fermented beverage made quickly. Wine requires far more time and patience.


A German chemist named Johann Peter Griess who lived from 1829-1888, developed the chemical reaction that allowed the synthesis of azo dyes to be made. Griess led a dual life. He worked for the brewery Samuel Allsopp and Sons in the central part of the United Kingdom located between Derby and Birmingham. While he was part of the laboratory team for Samuel Allsopp, he simultaneously developed and sold a dye patent to BASF in Germany.


Samuel Allsopp appeared to have no clue as to the importance of what Griess was developing and let the two paths of his chemist’s work continue. The diazotization of analine and other aryl amines Griess investigated is credited with forming the basis for a burgeoning dye industry in Germany. The blossoming of German synthetic dye companies would economically overtake the brewing industry. Allsopp had a fortune making chemist on his staff but never realized the amount of money that could be made by focusing on diversify and expanding his brewing business to include a dye works. On an economic impact level, Griess gave Germany what it needed to grow a major dye producing industry.


The imbalance remained much the same despite the work by the British chemist William Perkins on the synthesis of mauve. The German companies were way ahead in the dye industry and the system of patent protection for companies that sought dye making processes like BASF, allowed them to control production.


However, some of Griess’ knowledge and work on dyes would be of use to the Allsopp brewery. Industrial history essays suggest that Griess worked with synthetic dyes in order to identify microorganisms that could lower the quality of the beer that was being produced. The sensitivity of microorganisms to staining by various colored dyes allowed them to be visually detected. Eliminating microorganisms that would adversely affect the taste of beer and promoting those that enhanced the flavor of beer was a primary reason Allsopp hired a team of chemists for his brewery.


History records the explosion of developments in the dye industry in the latter half of the 19th century. The hunger for fabrics with amazing color ranges was fueled by the azo dye and coal tar dye industries. All of this serves as an important backdrop for what would happen in the art materials industry. (You thought I might never get to this.) For better, but for far worse, the art materials industry was tarnished by the introduction of synthetic dye colorants. Artists complained that their colors quickly faded. Suspicion was cast upon manufacturers. The use of the word “permanent” in the name of some colors, used even today, indicates a reference to the past alerting artists that a color with the word permanent in it did not contain dye materials. This was done to counteract the mistrust that artists had about the quality of some of the paints they could purchase.

Azo colors continued to flourish despite their problems in the art materials industry. Much of the manufacturing world of textiles and other items do not rely on color permanence to be a factor in their economic success. A patent for Naphthol pigment arrives 1911. The Cameo website states that Naphthol Red does not become popular until the 1930s. Once azo dyes were converted into pigments via the laking process, they became stable and could withstand light energy exposure without fading.


The incorporation of Naphthol Red into the line of oil and acrylic paints does not appear to become solidified right after the 1930s. After checking a number of old major manufacturing catalogs, one of the first appearances of Naphthol Red is in the 1974 Permanent Pigments list of oil colors. This is not surprising because Henry Levison was an innovative manufacturer who liked to push the envelope on the use of pigments. Naphthol Red appears in contemporary acrylic paint catalogs, but even now, the list of popular brands of paint containing Naphthol pigment is inconsistent. It is not a color that all paint makers deem to be a “must have” in their inventory.


I believe one reason that the color is not represented in all brands is that the cadmium colors are so close in hue that the need to add Naphthol is unnecessary. However, Naphthol pigments, are far higher in chroma and reveal this characteristic when mixed with white. They don’t turn slightly dull as cadmium colors do when mixed with white. Paint makers vary in their approach and philosophies about the colors they produce. Naphthol Red provides a modern, highly intense color that expands the chroma to a range of colors.


Overall, opinions on having Naphthol Red available or on an artist’s palette can run the gamut from never considering the color, to a must-have for creating works of art. While so much time is spent by plein air landscape painters knocking down the chroma of a color to match the hue and value of an outdoor scene, other painters relish the presence of a paint that yields so much intensity.


For those interested, Allsopp’s brewery still exists today. Founded in 1730, its nearly 300 years of existence stands as testimony to something they did right, despite not being savvy enough to capitalize on the work Griess was performing within their midst. Also, they make absolutely no mention of having employed the inventor of azo dye production. It does not fit in well with the beer making vibe that their website promotes. However, they do have a killer website feature that contains a history of the company in an interactive vertically scrolling timeline.


The Syntax of Color

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