Concentration of water-soluble ingredients on water-based paint, creating a blotchy, sometimes glossy appearance, often with a tan or brownish cast. More likely with tinted paints than with white or factory-coloured paints.

Possible cause

  • Painting in cool, humid conditions or just before they occur. The longer drying time allows the paint's water-soluble ingredients, which would normally evaporate, or be leached out by rain or dew, to rise to the surface before paint thoroughly dries
  • Contact of mist, dew or other moisture with the painted surface shortly after it has dried

 

Solution

Avoid painting in the late afternoon if cool, damp conditions are expected in the evening or overnight. If the problem occurs in the first day or so after the paint is applied, the water-soluble material can sometimes be rinsed off rather easily.

Fortunately, even more stubborn cases will generally weather off in a month or so. Surfactant leaching should not affect the ultimate durability of the coating. For more information, please consult our detailed Technical Advice note on the topic.


More problem solving advice

Yellowing

Development of a yellow cast in aging paint solvent-based enamels

Lapping

Appearance of a denser colour or higher gloss where wet and dry layers overlap during paint application.

Wrinkling

A rough, crinkled paint surface occurring when paint forms a 'skin'.