YInMn Blue

 Portrait of the Hon. Mrs Ernest Guinness (Frank Dicksee, 1912) oil on canvas

Of all the colors in my paintbox I am most dissatisfied with blue.  There are a lot of strong greens and there are vivid cadmium yellows, oranges, and reds.  There is ivory black which as dark as the depths of the void and dioxazine violet which is a great purple, but blue is a difficult color.  The brightest blues of the sky are from sunlight which has been scattered by the atmosphere.  The blues of bird feathers and butterfly wings are from careful refraction of light from reflective structures in the wings: if you ground peacock feathers fine enough there is no more blue….

The main blue pigments in the painter’s palette are cobalt blue (which is ancient and robust but a trifle subdued) ultramarine blue (a sulfur-containing sodium-silicate) which inclines toward purple, and cerulean blue a sky blue cobalt stannate which is painfully expensive.  Oh! there is a manganese blue out there in the paint stores, but I never used it until I bought a little tube a month ago,  so we’ll see how it turns out: it is sort of a tropical powder blue.  They are each beautiful but they each have their problems and none is the pure royal blue in the center of the spectrum which is bright, non-toxic, and lightfast (although the poisonous cobalts and…ultramarine too… last through the long ages).  This is why I was excited when my old painter friend Brendan (a raven painting specialist) sent me a link to an article about a new blue pigment.

YInMn blue

The new blue is called YInMn blue.  Discovered a couple of years ago by Robin Young, the new blue is lightfast, stable, and seemingly nontoxic (although sometimes in the past problems have taken a while to become evident).  The new blue is made of yttrium oxide, indium oxide, and manganese oxide.  It seems to be extremely lasting, and best of all it is very very blue.  Unfortunately, right now it is expensive (and the paint companies are still testing it out), but I have a feeling it might hit the market soon, and whatever its faults it can’t be worse for one’s health than carcinogenic cobalt.

Kudos to Robin Young for the new color.  I can’t wait to get a tube and paint some truly blue flounders…speaking of which, i better head back to the easel.

 

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Sun Purple

Lightly purples antique commemorative platter

In the 1860s the formula for making pressed glassware changed. Manganese was substituted for lead to act as a stabilizer and to make the glass brighter and clearer.  Nearly every major American glass manufacturer used manganese dioxide for such a purpose until 1915, when industrial chemists realized that selenium made for a better stabilizing/clarifying agent.

Manganese glass under blacklight

Because of the nature of manganese, the glassware manufactured during the late nineteenth century has some unique properties.  Original manganese glassware glows brightly under a blacklight (although vaseline glass, glass tinted yellow with uranium does the same thing).  When exposed to the sun over the years, as in a bright kitchen or a window, manganese glass takes on a slight amethyst purple cast.  Glass objects with a faint hint of sun purple betray their provenance, but they also lose some value–since antiques dealers regard the effect as “discoloration”.

Vintage “Sun Purple” teacup

However, some people became obsessed by the sun purple effect and put their antique glassware outside for months in order for it to fully turn cloudy purple in the sunlight.  This “solarized” glassware could then be sold to novice antiques collectors (often with a little card explaining “sun-purpling”).  Dealers realized that the causative factor behind the color change was ultraviolet radiation, and so instead of putting glass outside they exposed it to radiation from UV sterilizers (a common anti-microbial tool in bio labs and hospitals).  As you read this, somewhere out there is a room full of ornate glass pitchers, sugar dishes, and goblets being irradiated with blistering ultraviolet waves!

A germicidal cabinet!

Seasoned glass dealers are aghast at the practice, which leaves everything a murky washed-out pale purple.  Additionally there is glass currently being deliberately manufactured to resemble the manganese purple solarized glass.  To confuse the issue even further, there is also glass manufactured in a robust shade of purple (for people who like purple) which is named “amethyst” glass.

Antique “amethyst glass” pedestal vases (always meant to be purple)