The Vallejo Weathering Effects range, have been formulated with permanent pigments and water-based acrylic resins, have been developed to represent the effects of time and weather on models and dioramas.

Humidity generates slime and verdigris on wood, tree trunks, rocks, stone walls, moorings and pilings, in different colors, depending on the humidity. Slimy Grime Dark recreates the darkest shade, a black green.