The effect of different size–luminosity relations on the BH mass estimation. The figure compares the BH mass estimations of the sample LRDs, assuming the typical R_BLR–L relation calibrated for the AGN accretion disk (x-axis) and assuming that BLRs are just at the photospheric radius of the blackbody envelope (y-axis). Plots are color-coded by the blackbody temperature (T_BB). This demonstrates that using the typical R_BLR–L relation can overestimate the BH mass by ∼1 dex due to the different R_BLR estimations.