White chalk paint yellows primarily because it is porous and lacks a protective barrier.
Chalk paint's porous nature allows underlying substances or environmental factors to penetrate the paint layer, leading to discoloration. Here's a breakdown:
- Porous Paint: Chalk-style paints are inherently porous. This means they have tiny holes that allow liquids and gases to pass through.
- Lack of Barrier: Unlike some other paints, chalk paint often doesn't have a built-in sealant or protective layer.
- Substance Penetration: This porosity allows tannins from wood, oils, or even dirt to seep into the paint, causing yellowing.
The best way to prevent yellowing in white chalk paint is to create a barrier between the paint and the underlying surface or environment by applying a sealer or topcoat.
