With oils, it is impossible to obtain similar impastos to acrylics unless you first work with a pure impasto medium. Wait for it to dry and then apply the color. This is an economic solution for thick work. It is possible to use an acrylic type base impasto medium which will dry much more quickly.
A vegetable oil and natural resin based medium, which allows for different thicknesses and reliefs. It is a paste which is firm, yet light to use on the brush. For layers a few millimetres or more thick, it is essential to mix some Van Eyck medium or oil color into the impasto medium, in order to make the paste more flexible and therefore to reduce the danger of cracks appearing.
It becomes more matte by adding Turpentine spirits. Do not add drier.
Sennelier Impasto Medium 200 ml (6.7 fl oz) Jar.