TS EN ISO 19403-7

TS EN ISO 19403-7 is the standard for paints and varnishes that addresses wettability through measurement of the roll-off angle of a liquid drop on a tilted surface. It focuses on the dynamic moment when a drop starts to move on a solid surface, which makes the result useful for understanding practical liquid–surface interaction. From this dynamic measurement, advancing and receding angles can also be determined.

What the roll-off angle tells you

In general technical terms, the roll-off angle indicates how much a surface must be inclined before a droplet begins to slide or roll. This is different from a purely static contact angle, because movement introduces additional effects such as friction, roughness, surface heterogeneity, and adhesion. That is why the value is commonly used when assessing surface behavior related to easy cleaning, water repellency, and low-adhesion performance.

Where this measurement is used

• The document specifies a method for dynamic roll-off angle measurement on a tilt stage.
• Advancing and receding angles can also be derived from the dynamic observation.
• It is relevant for evaluating surfaces such as easy-to-clean or anti-adherent systems.
• The focus is on wettability behavior of painted and varnished surfaces, not on general coating performance as a whole.

This standard is concerned with measuring the interaction between a liquid and a surface, rather than describing appearance or broad durability properties. Interpretation therefore depends on general material knowledge, including surface chemistry, film structure, and application conditions. TS EN ISO 19403-7 provides a defined measurement approach for technical use in surface and coating terminology and evaluation.