B-V, B-R, V-R, and R-I colors of C/2017 K2 vs. time to perihelion and heliocentric distance, with the mean values from Table 4 compared with the average value of 25 active LPC from Jewitt (2015) (horizontal dashed black lines), and the Sun colors from Holmberg et al. (2006) (horizontal dashed orange lines). The vertical dashed line represents the perihelion, and the vertical dotted blue line represents the water-ice sublimation boundary (~3 au).