In coating applications, people always expect a smooth, even, and glossy finish. Yet in reality, many surfaces show uneven hazy spots or light–dark patches. This is the sign of the halo effect. The defect not only reduces visual appeal but also lowers the product’s commercial value. Understanding the causes helps applicators find proper solutions and effective prevention.
WHAT IS THE HALO EFFECT?
The halo effect in coatings is when the surface shows bright rings, hazy edges, or unusual glossy marks after drying. This issue often appears on decorative paints, automotive coatings, wood, or metal finishes under light reflection. For products with high aesthetic demand, the halo effect is almost equal to a failed coating.
It not only harms the appearance but also raises doubts about material quality and workmanship. An uneven surface is often judged as low grade, even if the paint still retains its technical functions.
MAIN CAUSES OF THE HALO EFFECT
Uneven solvent evaporation
Solvent plays a key role in dissolving resins and aiding coating application. When solvent evaporates too fast or inconsistently, clear boundaries appear between dry and wet zones. This contrast creates bright halos. It usually occurs with unsuitable solvents or when painting under high heat or strong wind. Without control, the surface ends up blotchy and rough.
Improper spray technique
The applicator’s skills greatly affect coating uniformity. If the spray gun distance is unstable, some areas become thick while others remain thin. Wrong overlapping or applying one heavy coat also prevents solvent from evaporating evenly. This is a common cause of the halo effect, especially with inexperienced workers.
Poor interaction between substrate and topcoat
The substrate acts as a base layer for adhesion. If it is dusty, oily, or not fully dry, the coating cannot bond well. In addition, incompatibility between primer and topcoat weakens adhesion. The result is uneven stains that look like blurred halos.
Light reflection between color layers
Each pigment reflects light differently. When a light shade covers a dark base, or the opposite, light scatters unevenly. The eyes then see cloudy patches or glowing rings. For decorative finishes, this halo effect causes discomfort and ruins overall color harmony.
Unsuitable application environment
Environmental factors directly affect evaporation and adhesion. High temperature makes solvent flash off quickly, leaving marks. Low humidity prevents smooth leveling. On the other hand, too much humidity makes the film cloudy. Strong winds during spraying scatter paint particles, producing uneven bright and dark zones. All these conditions contribute to the halo effect on the surface.
CONSEQUENCES IF THE HALO EFFECT IS NOT TREATED
Without recognition and correction, the halo effect leaves lasting damage. First is appearance: a blotchy surface lowers product value and often fails quality standards. In industries such as automotive, furniture, or decorative paints, this defect may cause customer rejection.
In addition, uneven coating layers degrade faster. Thin or poorly bonded areas peel off under weathering or mechanical impact. This shortens coating life and increases maintenance costs.
VICHEM – OFFICIAL DISTRIBUTOR OF CERTIFIED CHEMICAL ADDITIVES IN VIETNAM
Vichem is an authorized distributor of chemical additives with full legal certification in Vietnam. We not only provide high-quality products but also deliver international-standard aftersales services. Our services include:
- Technical consulting: Guiding customers to select the right product for each application.
- Color matching tests: Our experts conduct paint blending tests to ensure results meet design standards.
- Application support: Assisting clients in integrating additives into production lines for optimal efficiency.
For more details about our products, please contact us via:
📞 Hotline: 08 1790 1790
📧 Email: contact@vichem.vn
🔎 LinkedIn: Vichem JSC
🌐 Website: www.vichem.vn
📌 Facebook: Vichem JSC
