Professional level acrylic medium. Apply layer of crackle over a dry, permanent, water-based painted surface. For larger cracks apply a thicker layer of crackle. Allow crackle to dry up to 12 hours. Use a soft brush to apply a thin coat of water-based colour. Do not overwork the surface in order to avoid reconstituting the medium and it blending with the colour. Matte or gloss finish will depend on colour used. A water-based finish coat is optional.