Paint en plein air. Is that bad English or good French?
Online oil painting lessons en plein air, a la fresca,
In other words, outside or in the fresh. I suppose one can paint en plein air, in oils acrylic, egg tempera or any other medium of choice. Whatever you do, have fun.
En plein air is a French expression which means "in the open air", and is particularly used to describe the act of painting outdoors, which is also called peinture sur le motif ("painting on the ground") in French. ~ Wikipedia