The effect of titanium white, zinc white and lead white on the drying properties of poppy, walnut and linseed oil are analyzed by differential scanning calorimetry (DSC). All of the fresh films undergo complex thermal transitions between -100 and O°C. For some of the dried films subambient transitions that resemble glass transitions occur at about -30 O°C. After exposure to certain solvents, these sub-ambient transitions disappear or are reduced significantly. It is suggested that samples with diminished sub-ambient transitions become more brittle as a result of the loss of materials that act as plasticizers.