Winter dusk cheats the eye long before it flatters the sweater. Across the sky, the solar spectrum skews toward longer wavelengths as shorter blue and violet bands are stripped out by Rayleigh scattering in the thickening atmosphere, so the illumination hitting that supposedly neutral cotton is already biased, already warm.
The sweater itself stays stubbornly dull: its fibers still act as broadband scatterers, reflecting most visible wavelengths in roughly equal measure, the textbook definition of white. Yet human perception does not report spectra; it edits them. Through chromatic adaptation and color constancy, the visual cortex quietly discounts the ambient tint so walls and skin still feel normal, but it never fully cancels that amber cast on textured fabric.
What looks like a golden glow is really a negotiation between physics and biology. As luminance falls, rods share the workload with cones, the Purkinje effect nudging sensitivity while edge contrast on ribs and seams grows sharper against the darkening room, so the same unchanging knit becomes a kind of optical exaggeration of warmth, authored by falling light and a recalibrating brain.
