Comparison of observed OV line intensities with the fitted model (I ∝  |φ| ^δL^λ) for optimum δ and λ, for active regions 1 (top), 2 (middle) and 3 (bottom), using 4′′ × 4′′ pixels. Intensities are in units of erg cm^-2 s^-1 sr^-1. The continuous line are fitted values, sorted in ascending order. Crosses are corresponding observed intensities. These plots include all pixels with  |B|  > 90 Mx cm^-2.