What type of material is used in varnish?

Varnish is typically made from a combination of resin, drying oil, and a solvent. The resin can be natural, such as amber or shellac, or synthetic, like polyurethane or acrylic. The drying oil, often linseed or tung oil, helps to improve adhesion and flexibility, while the solvent, usually mineral spirits or turpentine, aids in application and evaporation. The resulting mixture forms a hard, protective finish when applied to surfaces.