Saturday, June 28, 2014
I have completed upgrading two wax writing tablets to make them more like medieval tablets.
The first is a triptych, probably made by Gary Link. and purchased at Pennsic. The second is a diptych sold by Historic Enterprises.
Tablets, Wood or Otherwise
The statutes of the Parisian tablet makers in the 13th century describe boxwood as the preferred medium for the tablet, although the wood of cedar, beech, ebony, brazilwood and cypress were also used, as well as ivory.
The wax cavity for the triptych had rounded corners, probably produced with a router.
I used a butter knife, heated in hot water, to push wax back from the corners of the tablets and squared them off with a wood chisel.
The process resulted in some splits in the wood. Even though I thought I had repaired the splits with glue, when I attempted to smooth the wax tablets by reheating them I lost a significant amount of the original wax, both through leakage through cracks in the wood, and because my oven racks were not perfectly level. Ultimately I got the best results by brushing on the hot wax and burnishing it smooth with a hot spoon. It does not need to be thick. If we had a hair dryer that would probably be useful.
The Historic Enterprises diptych was probably made from Sheesham or Shisham wood, often used in India.
Beeswax for writing tablets seems to have been mixed with resin, such as the terebinth resin added to medieval sealing wax.
Dammar resin is added to the wax for modern encaustic painting to add toughness, hardness and gloss, and to raise the melting point. A typical ratio for encaustic painting is one part Dammar resin to six parts beeswax, which yields wax that is harder than desirable for a writing tablet, hard to write on with a stylus and even harder to erase.
I have been unable to obtain terebinth resin, but I have experimented with mastic resin. Terebinth is produced by the terebinth tree, Pistacia terebinthus and Pistacia palaestina. Mastic is produced by the mastic tree, Pistacia lentiscus. They are members of the same genus, and so closely related that Pistacia saportae is believed to be a hybrid between P. terebinthus and P. lentiscus.
Mastic and dammar have similar properties when used as a varnish or to temper wax, but less dammar needs to be added to the beeswax for the same hardness, and mastic is much more expensive.
I experimented with a mixture of mastic and beeswax, in the proportion of the above recipe. Mastic has a higher melting point than beeswax, so I melted it first on a pan with a digital thermometer, and then mixed in beeswax. The result, as expected, was harder than untempered beeswax, with a higher melting point. It seemed somewhat softer than a typical recipe for contemporary encaustic medium which uses one part dammar resin to six parts beeswax, but a dammar based recipe could achieve similar hardness by adding more beeswax.
Wax for wax tablets would probably use a higher proportion of beeswax than sealing wax. Artists' encaustic medium would serve well as sealing wax, but I believe from my experiments that three parts beeswax mixed with two parts encaustic medium would serve better for a writing tablet. This is based on my experiments with the Enkaustikos brand of wax medium.
A well stocked art supply store can provide encaustic medium, either premixed with pigment or not. I mixed this with yellow refined beeswax. Alternatively, you could buy Dammar resin, beeswax, and pigments as separate ingredients, and mix them. Dammar resin has a higher melting point than commercial encaustic medium, so the mixing process is tricky.
The wax used for the Historic Enterprises diptych is strange stuff; it is softer than natural beeswax, and smears easily. I used a heated plasterers spatula to remove it and replace it with tempered beeswax.
The Historic Enterprises diptych is thick, coarse and robust compared to extant tablets. It works best as a tablet for a young child, whose parents might well prefer robustness and sturdiness over the delicacy and finish they would want for their own use.
Black wax tinted with some form of carbon black seems to have been the most popular choice for wax tablets, but red, green and yellow appear in iconography and written sources. Yellow was probably simply natural beeswax without any pigment.
Red and green tints in sealing wax were produced with vermillion and verdigris but other pigments may have been used for wax tablets. Vermillion and verdigris are highly toxic and/or unstable. They provide vibrant colors, but these may not be optimal for a writing surface.
Cadmium red, a 20th c. pigment, produces a similar range of hues to vermillion, also called China red or Cinnabar. Cadmium red is also toxic, but not as extremely as vermillion.
Venetian red produces less saturated and brilliant hues than vermillion, not necessarily a bad thing for a writing surface.
Green earth is less saturated and intense than verdigris, but more stable, less toxic, and frequently used in in medieval painting. A wax tablet tinted with green earth provides a pleasant writing surface.
There were several ways to keep multiple wax tablets together. They could be housed in a leather holster, like playing cards in a box. They could be joined by a single rivet at the top and open like a fan. They could be bound by a strip of parchment or leather glued to one side of the tablets like perfect binding.
Alternatively, they could be bound with linen or other cord or thread, similar to the Coptic binding used since the second century to bind codices of papyrus, vellum or paper. This doesn't seem to have been the most popular method for binding medieval wax tablets, but the wood panels of both my sets of tablets was already drilled with pairs of holes close to the spine on each tablet, originally to bind the tablets with leather thongs, a method not seen in surviving medieval tablets.
However, some surviving medieval tablets do have holes in those locations, so I used waxed hemp cord to bind the tablets together in a way inspired by Coptic binding. It seems to work well.
I modified the Historic Enterprises bone stylus to more closely resemble the size and shape of surviving styli, shortening it and reducing the size of the broad end.
As usual, Karen Larsdatter provides many examples of tablets and styli in both contemporary art and extant artifacts. Her link to the wax tablets in Torun, Poland are currently broken. They can currently be seen here, here, here, here, here and here. Randy Asplund has more on tablets and styli.