After the ink drawing comes the imprimatura, a layer of red that covers the entire panel. The imprimatura is one of the hardest stages of the entire process (apologies for not having a picture of it), as the red tempera mixture must be made from scratch and is very finicky; it basically ossifies if left unattended for more than a few seconds. For this reason, it must be applied to the panel extremely quickly as any mistakes cannot be corrected. In addition, if the formula is the least bit off and it’s too opaque, you run the risk of losing your entire drawing. I’m very proud to say that I wound up with an extremely successful imprimatura (my first time doing it alone!), although to the observer it doesn’t look like anything spectacular… or really anything at all.
On top of the imprimatura comes a first underpainting which is done in white tempera. Here’s the underpainting:
The purpose of this stage of the process is to render all objects that will appear in the painting using only light. The color that objects will have is disregarded at this part of the process, so things that are black will be rendered in the same way as objects that are white (ignoring albedo). This is also the stage at which objects are given their texture.
Coming up: the second underpainting in which objects begin to take on dimensionality.