Gamblin Galkyd Oil Painting Medium

Important Shelf Life Tip Store medium bottle UPSIDE-DOWN to prevent skinning over, congealing and solidification of this medium. Alkyd resin dries first by solvent evaporation, then by oxidation. The introduction of air space into a newly opened bottle permits some solvent ...Important Shelf Life Tip Store medium bottle UPSIDE-DOWN to prevent skinning over, congealing and solidification of this medium.

Alkyd resin dries first by solvent evaporation, then by oxidation. The introduction of air space into a newly opened bottle permits some solvent evaporation and drying – even with the cap tightly secured. As the medium is used over time, the air space in the bottle gets larger causing the remaining medium to dry out more quickly.

Upside-down storage has shown that storage upside down creates the best vapor lock limiting air flow in and solvent evaporation out. If your medium appears to have thickened even slightly, add a small amount of Gamsol and shake thoroughly until it is restored to its original consistency. Managing the viscosity of the medium from the moment it is opened will ensure the longest shelf life possible.

When decanting medium into a separate container, pour out only what you will use in a single painting session. If a larger size bottle of painting medium is drying out before you can use all of it, consider purchasing a smaller size next time. Store painting mediums in daylight to maintain their lighter colour.

All drying oils and alkyd resin mediums will deepen in colour when stored in the dark. Never use Galkyd as a varnish! Galkyd, Galkyd Lite or any oil painting medium, should not be used as a varnish. Using oil mediums as a varnish will increase yellowing of the painting over time.

Varnishes need to be clear, non-yellowing and, by archival standards, removable. Gamvar Picture Varnish meets all these criteria and is the best way to finish an oil or acrylic painting.