Farrow & Ball White & light tones Ceilings & walls Primer & undercoat, 2.5L. Farrow & Ball interior walls & ceilings primer can be used under Estate Emulsion and Modern Emulsion paints, to create a rich and long last finishing. Apply using a brush, roller or spray and leave for 2 hours to dry. This tin will cover up to 30m² per 2.5 litres on average. Primer & Undercoat by Farrow & Ball.