Chloë Holt RCA FRSA - “Umbra”Original oil, raw pigment, graphite and gesso painting by artist Chlo Holt RCA FRSA. Umbra means dusk in Latin. Chloes has of raw pigments in combination with her studio still life of artist brushes and paint pots harks back to Renaissance times of process. Involved highly with understanding her media the mussel shell is a reference to a time when artists created paint by hand and mussel shells held the precious paint. Framed size.