Egg tempera is a painting technique that has been used for centuries. It is inexpensive and easy to learn. If done right, the final product can be amazing. The picture below is an example of the tempera technique on wood (by Niccolo Semiticolo, 1367).
The version I am going to outline in this instructable is what I was taught by my teacher in grad school. I have not tried comparing it to other tempera techniques. If you would like to learn some other ways of doing this, you can visit www.eggtempera.com.
You can also find some history of egg tempera painting on Wikipedia.
Step 1: Why Egg Tempera?
The great thing about egg tempera is that you can use almost anything to make pigment. Tempera artists often grind and mix thier own pigments. The egg acts as the binder, and will stick almost any pigment to many different surfaces. This means you don't have to rely only on the colors offered by paint companies.
Personally I have never ground my own pigment. I prefer to use watercolor that is available at art stores for coloring. This color variety is plenty for my needs.
If you decide you don't want to use watercolor, and prefer to grind your own pigment, you might want to do a search to find the right way to process the materials.
If you would rather experiment than research, cool! But remember, WEAR A RESPIRATOR when grinding pigment. Things that aren't usually dangerous can become poisonous if ground to a super-fine powder and inhaled.
Step 2: Tools and Materials
You will need:
Pigment (We'll be using watercolor.)
A container (I used a cup. Probably not the best idea considering some watercolor paints are poisonous.)
Something to mix paint on (aluminum foil, wax paper, etc.)
Something to paint on (wood, paper, cardboard, etc.)
A slotted spoon (optional)
Paper towel (for cleaning up spills and drying brushes)
Step 3: Seperate the Egg Yolk
The part of the egg used is the egg yolk. We need to seperate it from the egg white. The clean way to do it is to break the egg and filter it through a slotted spoon. Gently shake it if necessary to get the egg white to slide off. I also turned the sink on and gently rinsed the yolk. Be very careful if you decide to rinse, a heavy stream will break the yolk.
The other way is to filter it through your fingers by passing the egg back and forth gently from one hand to the other. It just depends on you and your level of comfort with gooey things.
Either way, be careful not to break the yolk sack. What you want is a pretty golden-yellow blob.
Step 4: Mix in Vinegar and Water
Now we need to add the vinegar and water to the yolk. The vinegar keeps the egg from quickly spoiling. It will still go bad, but you will have several hours of working time before it begins to stink.
I was told the proper measurement is 1/2 eggshell of vinegar, and 1/2 eggshell of water. I did it with the eggshell, which leaked vinegar all over me. No surprise there. Next time I'll use a teaspoon. I think the idea is to just slightly cover the top of the yolk, so it isn't exposed to the air.
NOTE: On eggtempra.com the technique is a bit different. They don't use vinegar, probably because it is acidic and I think that can effect the archival quality of the artwork.
Step 5: Adding Pigment
Squeeze out a small amount of pigment on your mixing pallete (I use aluminum foil).
The way we were taught to use the egg medium is to pierce a small hole in the yolk with the brush bristles. Now the bristles have eggyolk (and a slight bit of water) on them. Mix the yolk with the paint using the tip of the brush, then apply it to the artwork. Over time the yolk will ooze out of the yolk sack, that's fine, it's still useable outside of the yolk sack.
The online tutorial is a bit different. It says to pierce the yolk sack and blend the yolk with water, then use the yolk/water mixture with the pigment. I have not tried this, but I'm sure it works just fine.
When you use the yolk straight, it is thick and dries with a slight shine. I would guess that cutting the yolk with water will be thinner with less shine.
Step 6: Color Sample
Here's the paint sample that I made. You can see that the paint is not totally opaque. Watercolor is designed to be semi-transparent. This allows you to build a painting up by layers. You can make the paint even thinner (and more transparent) by adding more egg or more water.
If you want opaque coverage, you need to use gouache (pronounced goo-ahsh). Gouache is watercolor, but it is designed to go on opaque.
If you are using multiple colors, be sure to have a container of water to rinse your brushes and paper towel to dry them.
Step 7: Drying and Clean Up
Now just sit back and let it dry. Remember, you just painted using EGG, it will dry, and it will begin to smell. Just put it somewhere out of the way and let it do its thing. After a few days the smell goes away, and you are left with a beautiful piece of art.
To clean your brushes, use some dish soap and water. Don't let the egg dry. If you do the bristles will be ruined.