I want to discuss the experience of painting ice and frozen water, which has specific optical properties that make it one of the more technically interesting materials to render.

Ice as a semi-transparent solid: ice transmits and scatters light. It's not transparent like glass — it diffuses light internally. The color of ice is a product of the depth (more depth produces blue-green tones from the absorption spectrum of water), the surface angle (reflective like water at grazing angles), and the condition (clear ice vs. frosted ice vs. snow-covered ice).

Frosted ice: diffuse, matte, lighter value than clear ice. The frost crystals scatter light broadly. The color is close to the ambient light temperature with reduced saturation.

Clear ice: partially reflective, partially transparent. Reflects sky and surroundings in the manner of water, but with less distortion. Shows the layer structure and air bubbles within.

Painted ice technique: start with the underlying form's color (the water, earth, or object beneath) then overlay the ice transparency gradually. The surface reflections are added as a final separate pass at reduced opacity.