Friday, 14 March 2014

Zen and the art of tempera medium

Magic potion ingredients
Why is adding a layer of egg-tempera medium over the under-painting not only a practical, but also a philosophical and spiritual experience?

... because, having taken to doing my underpaintings using Chroma Atelier interactive acrylic, to avoid the extended drying times of oil glazes in this benighted climate, (I have waxed unlyrical before about the fact that an oil glaze that took a couple of hours to dry when I was living under the Spanish sun now takes a couple of weeks in a more liberally humid mid-Wales), it is necessary to prepare the surface in a suitable way to get the final painting in oils to actually stick, without it embarrassingly parting company with the canvas at a sensitive stage of my career.

Egg-tempera medium is an emulsion, which is to say it contains both oil and water bound together precariously in a more or less stable mixture by the addition of a binder - in this case a beaten egg. I quickly brush on a quick even layer over the completed acrylic underpainting, to which it sticks nicely on account of being water based, and when it's dry it makes the perfect base on which to begin painting in oils, to which it sticks nicely on account of the varnish component, which contains resin and turpentine.

A practical measure then, for convenience's sake, but also a gateway from one realm to another. It marks a transition from the modern technological water-based world of working with acrylics to a realm of working deeply rooted in ancient traditions - the alchemical  discipline of oils and tempera.  I leave behind the modern and embrace the world of Leonardo and Michaelangelo.

Not only a gateway, but a transformational passage - the early stages of the painting are a technical and mechanical process, optically mixing glazes of primary colours masked by opaque white, carefully blalncing the textures of the different layers to create a 'monochrome' ground which is made, on closer inspection, of carefully controlled rainbow colours. At this stage I can still see distinctly and separately every constituent part of the process up to that point, like a complex technical drawing.  When the tempera medium is applied, however, it is a unifying force, binding all that has gone before into a single surface, a blank canvas that is no longer blank, ready for alchemical transformation.

From this point, anything can happen.

Recipe for egg-tempera medium (adapted from a recipe given by Ernst Fuchs):

1 egg
Dammar varnish (I use Kremer Pigmente no. 79300)
Refined linseed oil
De-ionised water

  1. Break the egg into a ramekin and with the tines of a fork, remove the amniotic sac from around the yolk.
  2. Put the egg into a small jar, screw on the lid and shake until the yolk and white are completely mixed.
  3. Add an equal quantity of dammar varnish and a few drops of linseed oil.
  4. Seal and mix again.
  5. Double the volume with distilled/deionised water.
  6. Mix for a last time.
The sealed jar will keep for up to 2 months in the regfrigerator. A slight smell of rotten eggs is nothing to worry about as the turpentine acts as a preservative. Discard if it gets too bad or if it curdles to the point where it can't be remixed to a smooth emulsion by vigorously shaking to jar.

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