Left panels: 2D scatter plots of B vs. γ for all points within the sunspot’s boundary at the three optical depth nodes (from top to bottom, log (τ) = −2.5,−0.9,0). Right panels: the same but only for pixels in the penumbra. The vertical dashed line in each panel represents the location of γ = 90°. A black box is drawn at log (τ) = 0 to identify/outline the umbral pixels, spine pixels in f) (see Figs. 12a and b for where these pixels are located in the sunspot).