A thin contaminating layer that reduces how readily water spreads across a glass surface, often causing beading or uneven wetting.
GlassRenu · Educational illustration
Meaning and boundaries
Water beading can also result from an intentional hydrophobic treatment, coating, surface texture, or incomplete rinsing. Wetting behavior alone does not identify the contaminant.
Why it matters in glass restoration
Uneven wetting can reveal invisible oil, silicone, or organic films that affect inspection, coating performance, and restoration uniformity.