Making Copper Resinate Green — The Transparent Glaze of Medieval and Renaissance Painters

Copper resinate is a transparent, intensely green glaze pigment made by dissolving verdigris (copper acetate) in a natural resin — traditionally Venice turpentine (larch balsam), or dammar/mastic resin dissolved in turpentine spirits. The result is a deep, luminous, transparent green that was one of the most important glazing colours in European painting from the 14th to 17th centuries.

Unlike the opaque mineral greens (malachite, green earth), copper resinate is transparent — light passes through the green glaze layer and reflects off the white ground or underpainting below, creating a luminous, jewel-like depth. This transparency made it invaluable for painting foliage, drapery, and jewels. Giovanni Bellini, Jan van Eyck, and Raphael all used copper resinate green glazes extensively.

SAFETY WARNING: This process involves handling verdigris (copper acetate), which is TOXIC if ingested and irritating to skin and eyes. Heating verdigris releases acetic acid vapour. Hot turpentine is FLAMMABLE. Work in a well-ventilated area, wear gloves and eye protection, and keep away from open flames. Use an electric hot plate or water bath, never direct flame.