Tuesday, November 28, 2006

Egg Tempera Class at the V&A: the pigments and the grinding

Following on from yesterday's post about last week's Egg Tempera class at the V&A, today's post is going to deal with the pigments we used and the grinding process.

Pigments

The pigments we used came from L. Cornelissen & Son in London. Some came in packets, some in small jars and some in very small jars - the more expensive the pigment, the smaller the container! This is Cornelissen's list of pigments; quantities and prices (pdf). It starts with the pigments, ordered according to colour group, but also includes other supplies. Note as indicated on page 5, Cornellisen also supply small quantities of pigment for artists using egg tempera to sample and others also requiring small amounts. Descriptions of the pigments producing early colours are listed on page 6 along with references to publications providing more information about them.

Cornelissen have been established as "colour men" (the term used for those who supply pigment to artists) since 1855 and are based in central London (at 105 Great Russell Street), very close to the British Museum. Their shop is well worth a visit for anybody wanting to get a taste of a traditional art supplies shop. AP Fitzpatrick just up the road from me in Bethnal Green also supplies pigment to artists - but doesn't have a website.

The following pigments were available in class:
  • Blues: Ultramarine Blue; Lapis Lazuli Dark; Smalt Dark
  • Reds: Alizarin Crimson, Red Ochre; Rose Madder Genuine
  • Yellows: Indian Yellow Tartrazine; Gamboge; Yellow Ochre
  • Greens: Green earth light; Verdigris; synthetic Malachite
  • Flake White
  • Ivory Black
In addition to this, Prof Wallace recommended azurite for sky colours.

Cennino Cennini writes about all the pigment colours used in fifteenth century Italy in section 2 of "Il Libro dell Arte". Another book recommended by Professor Wallace which provides a lot of good information about pigments is "The Artist's Handbook of Materials and Techniques: Fifth Edition, Revised and Updated (Artists' Handbook of Materials and Techniques)" by Ralph Meyer.

Now, as regular readers will know, I like collecting, organising and sharing links to websites that provide good information as a resource for artists. So - it will come as no surprise - I've created a new squidoo lens to organise all my new links to websites about egg tempera and this also contains other links to information about pigments - including pigment suppliers in the UK, Europe and the USA. "Egg Tempera: Resources for Artists" is set up pretty much along the same lines as my other squidoo lens. Please let me know what you think of it either on this blog or in the feedback section of the lens.

Producing egg tempera paintEgg tempera uses an egg yolk to bind the pigment. Cennino Cennini writes about why you need to use a town egg (with a lighter yolk) rather than a country egg when attempting to paint fine skin tones. You can experiment to see the impact that different colours of egg yolk can have on egg tempera. Country-fed chickens are good for orange!

Prof Wallace showed us how to create egg tempera paint. You can also see a more detailed description of how to do this here and there is another demo with photos here.


Click on the photos to see more a larger image. In summary the process for producing egg tempera paint was as follows:
  • set aside a quantity of pigment on a very hard (glass) grinding surface and check to ensure there are no lumps (you will also need to ensure that the glass does not move around while grinding takes place).
  • extract a yolk from an egg. One way of doing this is by placing the egg yolk in the palm of your hand and letting the egg white run off until there is none left (see photo). Then roll the egg yolk between your fingers and prick the sac from underneath so that the yolk runs out into a small clean container and the sac is left in your hands. Alternatively if you acquire the skill the egg sac can be squeezed (see photo). The egg yolk released from its sac then needs to be covered by cling film to keep it fresh. Ideally you need a small sterile container with a lid.
  • A fresh egg should be used each day so only make enough paint to use that day.
  • a palette knife is then used to mix a small quantity of water and then egg yolk with a small quantity of pigment. The mix will vary according to the type of the pigment - some need a lot of yolk while others need very little. Some pigments work best if ground with water first and then egg added.
  • The pigment is ground (see photo) using a glass muller with a ground base which looks rather like a paper weight with a knob on top. Grinding continues until the pigment mix is the consistency of thick cream. The egg tempera mix dries very fast on the grinding plate and it can be scraped down and reused for the next pigment very easily.
  • Egg tempera paint should be kept covered while not in use, otherwise it will dry out and become very difficult to use. Once it's got a skin you've got a problem. Suasage skins used to be used in the past - cling film works well now.
I found it worked best for me if I extracted a small quantity of creamy paste and then mixed this with a few drops of water in a separate container just before I was going to use it.

The main problem for me and my hand (with its tenosynovitis) is that I discovered that the grinding would quickly become a problem for me. Prof Wallace advised that it was possible, if not engaged in conservation work, to use very good artist quality watercolour paints containing high concentrations of artist quality pigment plus egg yolk. This is because watercolour paint contains the most finely ground pigment of all paints. The basic principle of creating egg tempera is that a pigment paste is mixed with egg yolk. Water should not be added if using watercolour paint plus egg yolk.

Tomorrow I will be telling you all about how I got on with actually painting with egg tempera!

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2 comments:

Alison said...

Well, I know I will never make time in this life do this but it's very interesting to read about it and nice to think of you having fun doing it :)

Katherine said...

Thanks Alison - have a read of the next post. There is a solution to the time issue!

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