An oil painting of any sort needs to dry for a considerable time after it is complete and before the final layer of varnish is applied. The time depends on the thickness of the paint applied and the types of mediums used, however a 3 to 6 month period can be expected.
Depending on the needs of the client, Elizabeth Whelan can apply a thin layer of matte damar varnish at the completion of the painting in order to deliver the portrait in a timely manner, and at a time 6 months or so later either she, or a local framer, can apply the final layer of varnish after the painting is completely dry.