This water-based size comes in the form of a milky glue that dries clear and is suitable for applying the gold leaf. The solution is to be applied to the surface you want to apply the gold leaf, and can be applied even on wood, cardboard and porous substrates. Once the size has reached the point that it feels as tacky as sellotape, then this is the correct time to apply the leaf. Surfaces that have been gilded using water-based gold size will have a more matt appearance than those gilded using oil-based size.