Bleu Français – part I

Pierrefonds French Art Nouveau Vase with Blue Crystalline Vase (LEO Design)

After yesterday’s journal entry about American artist Charles Jasper McLaughlin—who studied and painted in Art Nouveau France—I’m inspired to share, over the next few days, a handful of French Art Nouveau ceramic works (all blue), now in-store at LEO Design.  Some were (possibly) crafted during the time McLaughlin was studying in France.

First up: a classic, high-shouldered vase by Pierrefonds with an exceptionally rich crystalline glaze (Pierrefond’s signature aesthetic).

Glazing is a thin layer of glass, whether in a window or on a vase.  In a crystalline glaze, the crystals are concentrations of zinc silicate which form during the cooling process.  To achieve a crystalline glaze, two key steps must be taken.  First, zinc oxide is overloaded into the cool, liquid glaze.  Such an over-saturation of the chemical remains suspended while the glaze is hot; but, once the glaze cools, the chemical separates from its suspension and forms crystals—much like sugar will crystalize out of heated sugar water as the solution cools.

The second necessary step is the cooling process itself.  To form a crystalline glaze, the kiln is fired-up quickly to a temperature over 1800° F.  After a short period, the kiln is lowered some 400° and held at this temperature for hours.  It is at this temperature that the crystallization process occurs.  And, to produce ring-like crystal growth, the kiln temperature can be spiked and lowered repeatedly to start and stop the crystal growth process.  Because of the extra-hot kiln (at least at the beginning of the firing), a lot of glaze tends to run-off crystalline vases (leaving “puddles and rivulets” of glaze near the bottom of the vase).  To correct this, the bottoms of most crystalline vases need to be manually ground-down after firing and cooling.

Opening a ceramics kiln after a crystal glazing run is like opening presents on Christmas morning—one never knows what’s inside!  Although glaze masters learn to influence the process of crystal formation—and spend hours and hours running tedious experiments to hone this skill—there is still a large degree of unpredictability and happenstance involved. There is always a high failure rate with crystalline glazing and, it goes without saying, no two finished pieces are ever the same.

More Bleu Français tomorrow.