Here's what has been happening this afternoon. I first sealed the pencil drawing to the canvas using a thin wash of burnt umber artist quality acrylic and then worked into it with heavier dilutions of the same pigment. I have taken care to make use of the under-drawing. I have worked into the darker areas and details with acrylic because of the quick drying nature of the medium. At the end of the day I again sealed the canvas with a thin layer of liquin and turps ready for more underpainting tomorrow. It's a bit long winded but I think it is worth it.
Here is a better photo of the recently finished painting
Peace and love