The primary way to preserve mixed acrylic paint and extend its lifespan is by preventing air from reaching the paint.
The length of time you can keep mixed acrylic paint usable largely depends on how thoroughly you keep the air out of its container.
Here's a highly effective method based on keeping air out, particularly when your paint container isn't full:
Simple Steps to Preserve Your Mixed Acrylics
When you've mixed a custom color or have leftover paint in a container that's not full (for example, if the jar is half empty), direct contact with air is the biggest enemy. Here's how to combat it:
- Check the Container Level: This method is especially useful when the container has significant empty space above the paint.
- Prepare a Barrier: Get a small piece of plastic wrap (often called cling film) or a similar thin, flexible material like thin acetate.
- Place Directly on Paint: Carefully put a bit of clingfilm inside on top of the paint.
- Eliminate Air Pockets: Gently press the film down so it makes direct contact with the entire surface of the paint. The goal is to ensure no air can get to it underneath the film.
- Seal Tightly: After the film is in place, close the container (or other container) tight.
This technique creates a physical barrier between the paint and the air in the container, drastically slowing down the drying process.
Why Air is the Enemy
Acrylic paint dries through evaporation, specifically the evaporation of water in the mixture, which causes the acrylic polymer particles to fuse together. Exposure to air accelerates this process. By limiting air exposure, you slow down evaporation and keep the paint in a workable state for longer.
Summary of Preservation Tips
- Minimize Air Exposure: Always use airtight containers.
- Use a Barrier: When containers are partially empty, place plastic wrap or acetate directly on the paint surface.
- Seal Securely: Ensure lids are closed tightly.
Following these steps, particularly the method of using a barrier like cling film directly on the paint, will significantly help in preserving your mixed acrylic paints for future use.
