Tempera paint is made by binding dry powdered pigments together with a binding agent, also known as a medium. This process creates a stable and usable paint.
The Binding Process Explained
The core of tempera paint creation lies in the binding of pigment particles. Here's a breakdown:
- Pigment Selection: Dry pigments, finely ground powders that provide color, are chosen based on desired hue and lightfastness.
- Binding Agent Preparation: A binding agent, typically an emulsion, is selected. Common binding agents include:
- Egg Yolk: Arguably the most traditional and well-known binder. It creates a durable, somewhat glossy finish.
- Egg Tempera Emulsion: Whole egg is mixed with oil and water to make a stable paint medium. This reduces yellowing and cracking of the yolk-only formula.
- Casein (Milk): A protein derived from milk, providing a matte finish.
- Plant Gums: Such as gum arabic, offering flexibility and transparency.
- Glue size: A less common type of binder used on rigid surfaces.
- Grinding and Mixing: The dry pigment is carefully ground into the binding agent. This process ensures that each pigment particle is thoroughly coated with the medium.
- Consistency Control: The ratio of pigment to binder determines the paint's consistency and working properties. Adjustments are made to achieve the desired flow and opacity.
- Storage and Application: Once the pigment is fully dispersed in the binding medium, the tempera paint is ready for application, provided the nature of the binder allows for storage.
Key Aspects of the Binding Mechanism
The effectiveness of tempera paint depends on the binder's ability to:
- Adhere to the Pigment: The binder must effectively coat and grip the pigment particles.
- Adhere to the Support (Painting Surface): The binder must form a strong bond with the chosen surface, ensuring the paint layer adheres properly.
- Create a Stable Film: As the binder dries, it forms a solid, continuous film that encapsulates the pigment particles, protecting them and creating a cohesive paint layer.
Examples of Tempera Techniques
The choice of binder influences the application and final appearance of the painting. For instance:
- Egg Tempera: Renowned for its delicate, translucent layers and fine detail.
- Casein Tempera: Favored for its matte surface and suitability for large-scale murals.
