• Michael Skalka

Uranium and Copper Oxide Pigment

Updated: Feb 25


“She wore blue velvet

Bluer than velvet was the night

Softer than satin was the light

From the stars…”


(Bernie Wayne and Lee Morris, 1950)


Timing is everything. You walk down the street, turn left instead of right and suddenly run into an old college friend. He introduces you to his sister's girlfriend and …. twenty years later, you are married and standing on your front lawn playing catch with your teenager.


So the question is, could the element we know as uranium have been named Klaprothium or Peligotium? Perhaps.

In 1789, Martin Klaproth discovered a yellow precipitate derived from pitchblende. Believing this to be an undiscovered element, Klaproth named it after the newly found planet, Uranus. The planet was identified by the hard-earned efforts of the astronomer William Herschel in 1781. However, Klaproth had not taken the uranium refining process far enough. What he discovered in the pitchblende was uranium oxide, not the pure metallic uranium. In 1841 the French scientist Eugène Melchior Peligot reduced uranium oxide to reveal pure uranium.


Had Klaproth exercised his prerogative, he could have named the element after himself. Had Herschel been distracted while looking through his telescope, he might have missed discovering Uranus, leaving it for a future astronomer to find and name it something other than Uranus. Peligot having discovered highly refined uranium might have named it after himself or whatever else was trending at the time of his discovery. Peligot’s story does not end with the refining of uranium.


Peligot went on to other discoveries, as many good scientists seem to do. He identified the potential presence of glucose in urine that enabled the medical world to understand the functions in diabetes. Far less inspiring than uranium, but significant to the art world, Peligot created a hydrated oxide of copper that possesses a blue-green hue. This pigment appeared on the market around 1858 as Peligot Blue. It is historically unclear as to what Peligot was doing during the 17-year period following the discovery of refined uranium and the introduction of Peligot Blue. Given the dangerous nature of uranium, Peligot may have been suffering the ill effects of too much radiation, thus stifling his creative abilities to make more pigments.


While looking up the details of this pigment, an interesting twist appeared. It seems that many authors lump all copper-based pigments together. Azurite, Bergblau, Bice, Blue Verditer, Cendre Bleue, Lime Blue, Mountain Blue, Blue Ashes, Copper Blue and Bremen Blue describe various sorts of copper-related blue colors. Many of these colors have rich histories and stories to tell. Unfortunately, they are lost when scientists like Peligot who invent new and better pigments satisfy the desires of the marketplace. Many of the afore mentioned blue colors have exciting magical names but have fallen by the wayside. While one laments, bear in mind that copper carbonate pigments were fugitive and reactive in the presence of sulfur. While we are thankful for a wonderful array of permanent, stable blue pigments marketed today, one can long for a glimpse into the past to view the variety of hues attainable from copper-based colorants.


Besides the obvious reference to blue in both Bobby Vinton songs noted at the top and bottom of this Syntax of Color, another odd twist was discovered. Bobby was no stranger to blue. He cut a complete album of songs with “blue” in them. Further, the director David Lynch made a film in 1986 called Blue Velvet. In a scene from Blue Velvet, Lynch juxtaposed the dreamy, romantic tune “Blue Velvet” with a powerful jarring discovery of an ear cut from a crime victim’s head.


While van Gogh, also a powerful and jarring painter, befell a similar ear crisis, he is not closely associated with any of the copper-based blue pigments described previously. Evidence indicates that he used Prussian Blue in his paintings. That would have brought this story full-circle. Life does not always work out that way.


So, we return to lamenting over pigments long gone from the marketplace. These were deep blue colors that faded to dull, mossy greens. It’s too bad that they did not have the longevity we seek in the paints we use today. Perhaps we are better off without them. Still, we are sad.


“Blue on blue, heartache on heartache,

Blue on blue now that we are through,

Blue on blue, heartache on heartache,

And I find I can't get over losing you…”


(Music-Burt Bacharach, Lyrics-Hal David, 1963)


PS: Celebrate the 210th anniversary of Peligot’s birth on February 24th. A yellow cupcake with blue buttercream frosting would recognize the chemists discovery of pure uranium and the synthesis of hydrated copper oxide blue colorant.


The Syntax of Color

Original Grammar of Color Essay

Vol: 1 No. 13, (Published 5-25-05)

Revised, February 2021

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