Comparison of P_r in the V and R_C bands. (a) Each data point indicates the observed P_r of dark asteroids taken at the same phase angle in the V and R_C bands ($P_{\text{r},V}\text{ and }{P}_{\text{r},R_{\text{C}}}$, respectively). The marker indicates the asteroids’ ID. The solid black line represents $P_{\text{r},V}=P_{\text{r},R_{\text{C}}}$. (b) The difference between $P_{\text{r},V}\text{ and }{P}_{\text{r},R_{\text{C}}}$ depending on $P_{\text{r},R_{\text{C}}}$ is shown. The dashed lines indicate the standard deviation of $P_{\text{r},V}-P_{\text{r},R_{\text{C}}}$ , which is ±0.108%.