More practice. Here are some flowers I've painted in grisaille, this time done in cool grays. I just looked up a grisaille portrait workshop on Google, which suggests working in burnt sienna because that color holds up the best over time as an underpainting. Perhaps tomorrow I will try something in burnt sienna.
I think I should be working lighter if I want to glaze over these sketches. If my underpainting is too dark, the colors won't show up well. Practice. Practice.
An interesting website about the Grisaille, or Dead Coloring technique is Linda Coulter's site HERE: