I love making my own tools. The next logical extension to that is making my own consumables! Paint has existed in many forms since people were drawing on cave walls. More modernly we are most familiar with acrylic, oil, water and the miscellany of cans from the box and specialty stores. It wasn't until the 1500s that oil paints became popular, prior to that people, often scholars ands illuminators, crafted their own paints on a use by use basis. Paint comes down to a few simple properties: A binding agent to hold it together and stiffen and dry, a pigment to tint it to a needed colour and a thinner or solvent to increase or decrease the viscosity as needed. In the case of Egg Tempera, the yolk of an egg is used as the binder. It creates an incredibly hard and stable paint, there's a reason so many manuscripts and paintings still exist from hundreds of years ago- Egg Tempera is stable and archival; it's also made from simply available materials, even in the medieval world.

Supplies

At it's simplest tempera requires:

An egg
Water
White Vinegar
Pigment

For higher quality results also add:

A scale for accurate measurements
Dishes for mixing
Paper Towel for cleaning off egg yolk
Distilled water for increased stability
A Mortar and Pestle for creating your own pigments (or pre-made store bought pigments work just as well)
Syringes for easy adding of parts
Paint brushes
A surface to paint on, Tempera can be used anywhere paint would normally be used, traditionally would be used on wood plank canvasses.

Step 1: Separating the Yolk

First we need to separate the yolk from the rest of the egg. Crack your egg and try to split the shell roughly in half. This will give you two little cups you can roll the yolk back and forth between as the white drains into a dish below. Go slow and be careful not to puncture the membrane around the yolk. Once separated, set the whites to the sides (can be used for baking, lower cholesterol scrambled omelets or Medieval Glair, another type of paint often used on books)

Step 2: The Binder

Next we need to remove any remaining white from the yolk so we are only left with membrane and yolk. Take the yolk in your hand and roll it gently into the other. With the now vacant hand, wipe it off on some paper towel on the table in front of you, now roll the yolk back into that hand and wipe the other hand. Repeat this back and forth 5 or 6 times until the membrane begins to look dry and starts to stick more than it slides: this is when you are ready to pierce the membrane and collect the yolk. Over a new dish, roll the yolk up into your fingers and pinch the yolk. As the membrane breaks the yolk will drip out into the dish, keep your fingers pinched and hold on to the membrane, separating this film from the inner liquid will help make a smoother paint without any lumps.

Step 3: The Solvent

Now that the yolk is prepared we can begin mixing our ingredients. Remember: Tempera at its simplest is just 3 things - a binding agent (our freshly prepared yolk) a thinner to adjust viscosity and a pigment. As it is now the yolk is too think alone to work so we are going to mix it 1-1 with our thinner to make an easier starting place. That thinner you ask? Water! For the most stable paint using distilled water (water that has been boiled and then collected from the steam) will introduce the least impurities into the paint, but regular kitchen water will work fine as well though your results will vary more. Distilled water can be readily purchased or easily made yourself by boiling water and putting a sheet on an angle above it to have the steam condensate and drip down into a receiving container.

Here I'm using a scale (zeroed to the weight of the dish) to ensure my mix is very close to 1 to 1 by weight. That being said, this paint was being used long before digital scales were in use, the eyeball method will work just fine.

Step 4: The Mixture

Add an equal part of your separated yolk to the mix. As a way to make your paint even more stable, adding a drop (yes just a single drop) of white vinegar will help to balance the PH of your paint and even further increase it's stability and archival quality. Using a palette knife or brush gently mix your concoction together.

Step 5: The Pigment

Pigments can be purchased ready to go from a variety of sources or they can be easily collected and used from nature or even your kitchen. There are well established traditions of certain materials being using for specific colours. Woad for indigo, turmeric for orange, rose petals and beats for red, onion skin and celery seeds for yellow. There is a plethora of ways to make each colour and most likely ways that are unique to the part of the world you live in.

Today I am using charcoal to make black. Taking the charcoal I place it in a mortar and first crush then finely grind it into a soft powder with the pestle. The more time you take here the finer a pigment you will make and a smoother paint as a result.

Step 6: Pigment Meets Paint

To mix your paint up scoop some of your pigment and place it on a smooth hard surface such as a piece of glass or a granite slab. A kitchen plate would work well for this. Slowly start to add your egg mix into the pigment and using a pallet knife or brush begin to mix your paint into a cohesive homogenous paste. To increase the viscosity (make it thicker) increase the pigment. To decrease the viscosity, add more egg mixture. Alternatively to get a more water colour like paint thin with a bit more water to make your mixture more runny and less bound by the yolk.

Work in small batches. This paint will dry extremely fast, so only mix up what you plan to use shortly as large batches won't last. Having a larger amount of yolk mix and a selection of pigments and a palette will allow you to mix colours as you paint.

Step 7: The Painting

Play around with your paint to get a feel for it. Is your pigment mixed in well enough? Are there lumps in your pigment that should be ground down further before mixing? As you paint you may notice your tempera begins to thicken as moisture is wicked away by your brush. Adding a bit of the egg mix back in will help keep it at a consistent thickness as you go.

I wanted to create a wanted poster for my players in our DnD campaign where our Druid was seen as a shapeshifting crow leaving the crime scene. A murder of crows indeed.

Step 8: Conclusion

There's something so unique and special about creating your own paint. On one hand it's so simple and could be created by anyone for hundreds of years. On the other hand it's bespoke and of high quality, the extra little effort that sets a piece up a little higher than the rest. Happy Painting!