All through the history of the art, artists have used oils (fixed and essential) in order to hold the color pigments together while protecting them against undesired changes, create consistency and preserve the pigments in drying to a though, flexible layer. However, enough scientific knowledge is not available in the sense of properties of essential oils as paint thinners in the field of painting art and their usage. In the present study, effects of four essential oils (lavender, oregano, clove and turpentine) on total time required for complete drying, color properties (L*, a*, b*), composition of volatiles (GC/MS) were investigated. For this purpose, essential oils were mixed with oil-paint with ratio of 0.1ml essential oil in 1g color [white (W), yellow (Y), red (R) and blue (B)] until obtaining a smooth texture. The major volatile components found in essential oils were linalool (36.11%), linalyl acetate (33.62%) for lavender oil; carvacrol (70.72%) for oregano oil; eugenol (84.91%) for clove oil and α-pinene (88.55%) for turpentine. The shortest drying time was observed in W, Y and R and followed by B for lavender oil mixture. Different drying periods were found all colors and other essential oils while the longest one was belonging to oregano containing ones. With respect to color attributes, any important alterations in lightness (L*) among different colors, except white one, were not detected for different essential oils. For W, the highest L* was observed for turpentine where the lowest was belong to clove. Oregano and clove oils were found to cause slight increments in the yellowness of white paint (+b*). For yellow and blue pigments, the highest yellowness (+b*) and the highest blueness (-b*) were found for turpentine and lavender oil containing paints, respectively.
Thus, the study indicated that lavender has a great potential in paintings due to shortest drying time and the ability of bringing out characteristic properties of each color compared to other essential oils.
Keywords: Medium; Essential oil; Color; Drying time; Essential oil composition