Porcelain was first discovered by the Chinese; and so too was the process for making simple lithophanes. Baron Paul de Bourguignon, of Rubelles France, is generally credited with copyrighting the processes of Lithopanes in France in 1827. Porcelain was the favored raw material used in the processes.

Chinese potters employed the process to trace floral designs in the delicate walls of eggshell thin porcelain vases. There is little historical evidence indicating the exact origins of this technique in China, but it is certain that the knowledge predates the subsequent discovery by the Europeans.

Once the Europeans got involved, the designs migrated from floral to intricate human interactions and scenes. Children at play, animals performing, ladies in various settings, religious, hunting, scenic panoramas, and more.

Skilled German sculptors carved motifs into beeswax. Then porcelain castings were made. The effect in the porcelain comes from the variations in thickness of the translucent porcelain. The thinner parts let more light through and the thicker parts provide the darker shades. This way, the lithophane becomes like a three-dimensional painting with the light passing through, dictating the motif.

It was beautiful and became a rage in the Victorian period in Europe (circa: 1840 to 1920). They functioned as candle shields, night lights, lampshades, fire screens, tea warmers, and were hung in windows to catch the light.

These porcelain castings which, in ambient light, seem only to be bumpy surfaces form a vague picture. But, when back-lit, a beautiful, three-dimensional picture appears in full depth and detail.

The artist first drew his general design on the surface of the white wax. Then, with modeling knives, burnishers, and other tools, he sculpted the minute details of the subject chosen for reproduction.

From the wax carving, when finally approved by the master model maker, a plaster cast was made. This was the original die, which was used in molding the porcelain bisque. A moist porcelain paste was then skillfully pressed into this cast, picking up all the details in the carving. Close examination of this mold would reveal intricate surface detail.

During the porcelain casting process, the friction of the clay would swiftly wear these fine details out. Sometimes, as few as 20 castings would leave the image in the mold worn out. To address this problem, the artists developed master molds. Master molds were made out of a harder plaster than the production molds, and the image was reversed; like a negative. Production molds were then cast from the master mold, allowing many more lithophanes to be successfully cast.

The seemingly simple process of removing the thin moist panels from the molds required the highest degree of skill to avoid damaging the intricate details in the image. Since the panels were very thin and delicate, and the kilns extremely hot, many fired pieces were warped, twisted, and cracked. In addition, any slight impurity in the porcelain clay body showed up when the fired pieces were lit from behind. Therefore, the number of acceptable finished pieces to come out of the kilns has always been far less than the number that went in. Sometimes, only about 40 percent of the panels survived this process.

Since the earliest days of their production, these issues have challenged the makers of lithophanes. Only the most determined craftsmen could overcome these difficulties, and go on to produce these brilliant art pieces.

The Blair Museum of Lithophanes has the largest collection of these unique porcelain pictures in the world.

Go to http://en.wikipedia.org/wiki/Porcelain for more detail about the processes of making porcelain.