Wednesday, November 19, 2008
The Giotto Plaster of Paris Fresco Project- Finally!
I must apologize for my tardiness in posting this. Moving covers a multitude of indiscretions however and I will stick to that excuse :).
What you will need:
Plaster of Paris
Giotto Black Line
Plastic Plate with at least a half inch well
1. First prepare the plaster of paris. Directions usually call for a ratio of two parts plaster to one part water, but for this project equal parts works best.
Start by putting about one cup plaster in the plastic plate(you could also use a cheap and small disposable aluminum pan) and then add one cup of water. Stir with a plastic fork until all the powder is liquefied and then let it set. It should set up rather quickly, about half an hour or so. Because you want to paint on it while it is still a bit wet, don't wait much longer than that.
2. Tape your black line picture to the outside edge of the plate. I cut mine to the same size and shape of the inside of the plate which was a cool geometric shape. The plate itself was interesting enough to become a nice frame.
3. Trace over the image in the black line with a firm hand. Not to hard or it will crack the plaster but hard enough so that you feel the pencil pushing in to the soft plaster a bit. When you are all done you will have a relief of the black line image on the plaster.
4. Now you can paint! You can either use the tempera paint straight from the bottle on to the plaster or you can use the egg yolk mixture method that artists like Giotto and Michelangelo used. (Go here to see the how to and whys of the method).
The last thing the artist was about to say was how permanent the medium is. ( I would say so since Giotto's frescoes are over 400 years old!)
Most books will tell you to use tempera powder and mix that with a mixture of egg yolk and water, but I have mixed the egg yolk straight with regular tempera paint with excellent results. Generally you will want to mix one teaspoon of water per egg yolk and then mix with an equal amount of tempera paint.
5. When you are done you can add an acrylic glaze to protect the piece and make it shiny.
As the plaster and paint dry, the paint will become part of the plaster. It is a really cool process though definitely not one for sissies! It is not forgiving of mistakes or slow workers. This piece is pretty small and it will truly make you appreciate the wall and ceiling size murals of fresco painters like Giotto, Michelangelo, and Diego Rivera.