Oil paintings are works of art created by combining colors with a drying oil medium. The most frequently used medium is the linseed oil although walnut oil, poppy seed oil and safflower oil are also utilized. Choice of oil depends on its effects on the pigments, whether they dry faster or cause yellowish discolorations. The consistency of the oil paints may differ depending on the drying oil. According to Brian Thomas, he considered the development of Western oil painting occurred in four overlapping phases - line design, form design, tone design and color design. The line design was based on the association among outlines and shapes, which became a popular trend during the end of the Roman Empire and the emergence of the Renaissance period. Color alterations allowed outlines to be accentuated. Artists typically used distant and typecast symbols in their oil paintings. These symbols appeared vague to integrate a religious impression. Notable artists of t...