Head studies from moving subjects

Oil on canvas panels. Painted these at my workplace, about A5 in size.

They are painted from unposed subjects, with movement (sometimes drastic) and all that.

But it was a good test of how well I understand the structure of the head, as you have to use some mental perspective to account for the changes in angles and direction.

I'm not satisfied with the coloration, as with such 1 layer quick studies on a too absorbent surface, the oil gets absorbed into the panel too quickly, tending to shift the hue too warm.