I got re-interested again in glass color production techniques because of a nifty cloisonne plate for which a correspondent sent me some pictures. The pink background enamel seems very uncommon, which of course it might be if the glass batch required not only gold, but gold turned into a colloidal state by rather tricky chemical processes. The color seemed to offer a dating clue for the plate.

The use of selenium, erbium, neodymium is also a bit of a puzzle. Presumably this began in the late 1800s? A Czech glass importer once informed me that selenium-colored rose glass is tricky because it's extremely temperature-sensitive; a bit too much heat and it takes on a topaz tint, rendering it a more peachy or salmon color rather than a pure rose pink.

I know that when the Czechs started making transparent pink seed beads again after the factory reorganizations following liberation from the Soviet sphere, the first batches were a nice deep pink, but then subsequent batches were a lighter, more peach hue. Oddly, the peach-tinted glass is beautiful for its close resemblance to the rare padparadscha sapphire, and looks wonderful with turquoise.

Selenium rose glass can be separated from gold rose if the piece is translucent enough for examination with a pocket spectroscope - the selenium presents a two-color spectrum of a giant wash of scarlet against a black remainder of the spectrum. The red completely floods out all the other colors - definitely a retina-fryer!

blog flog time: two recent posts on pink enamels
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