Monday, June 4, 2018

Ancient Medium - Egg Tempera Painting, Part 4 - The Image and Applying the Pigment

Part 4 – The Image and Applying the Pigment

Starting an egg tempera painting on a clean gesso panel is a daunting process.  The gesso is highly absorbent and the first hundred or so layers of very diluted pigment vanish pretty quickly into the gesso, drying almost instantaneously. Lines drawn on traditional gesso once made cannot be erased, therefore, unless the painter is brave, works with a broad brush approach and understands the image and the medium, the image to be painted on the panel is usually planned out ahead of time, drawn on another surface, such as paper, and transferred to the panel. Before transfer papers the Old Masters would lay the drawing over the gesso or parchment and, using a sharp point dipped in ink, pierce the paper thus transferring the image as a series of dots. This can be done today using transfer papers and a stylus.  Another method is silverpoint (one of several types of metalpoint).  This was a traditional drawing method used by medieval scribes on manuscripts drawing out the image on parchment or a panel. The essential metals used were either lead, tin or silver, but today silverpoint is accomplished using a stylus with a small, fine rod of silver at the end that is drawn across the surface of the gesso making a mark.  This line is initially grey, turning to warmish brown as it is exposed to the air and the silver tarnishes. Silverpoint may remain as the final drawing or can then be painted.  The drawing can be transferred using the silverpoint step and then the painting begun.

Because the gesso is so absorbent layers of paint are built up gradually alternating warm and cool, light and dark, crosshatching and broad brush in a meditative fashion until the substance of the painting begins to emerge. The speed of this can be quickened by sponging or airbrushing the pigment on large areas such as sky or large color fields. Pigment is applied in greatly diluted strength because raw pigment is used without the buffer of layers of oily medium in between.  In egg tempera painting there is just the pigment, yolk and water.  If too strong a color is used there is often no going back, thus no way to correct a mistake as can be done with oil paint as it may take so many layers in egg tempera to lighten or darken that area that the paint becomes too impasto to be sustainable (impasto, as a technique, doesn’t work in the traditional sense of egg tempera painting).  Also, some colors are more intense than others and therefore cannot be corrected easily, if at all, such as using too much Prussian Blue, but some intense colors not formulated used as transparent hues can still be used as glazes if diluted sufficiently.  An egg tempera painter must know their colors, how the hues respond, the chemical makeup (toxicity) and how to use them effectively.

As already mentioned a respirator should be used when preparing the paint from dry pigment, but is not necessary once water has been added to create a paste.  Depending on how a painter works latex gloves may be necessary when working with toxic pigments for any length of time.

Depending on a number of factors (how the pigment is applied and the amount of tempering), the painter will occasionally gently sand the painting, or parts of it, during the process of painting with a very fine 2000 – 3000 grit sand paper.  An equally gentle buffing follows this sanding with cheesecloth or a cotton ball.  This removes rough spots, smooths out edges, or corrects insufficient tempering.  Too much buffing at this stage will limit adherence of future layers of paint so it is kept to a minimum.

Occasionally, if the pigment is too dry or wasn’t tempered enough, what’s known as a “nourishing layer” of yolk is applied to areas or to the whole painting.  This mixture is typically one part yolk to sixteen parts water and applied quickly over the intended area.

Next Up, Part 5 – Layers and Finishing (on June 11)