Facular contrast as a function of B_LOS/μ, and the number of pixels in each bin. Top: we computed the contrast curves using the combined SO/PHI and SDO/HMI data as well as the SO/PHI data alone in two μ intervals (0.1 < μ ≤ 0.3, right column, and 0.3 < μ ≤ 0.4, left column). We split the data into equal intervals of log(B_LOS/μ). The error bars represent the standard deviation of the pixels within each bin. We fitted a third order curve to the combined data points (continuous green line). Bottom: based on the number of pixels in each bin, we exclude from the plots SO/PHI-based data with μ < 0.2.