Color indices of the dynamically new comets against their heliocentric distances. Red circles indicate the comets from this study and blue circles denote the dynamically new comets selected from Jewitt (2015). Top Panel: all data points; the mean values calculated for each of subsamples separately are inserted in the figure. Bottom Panel: pre- and post-perihelion observations separately assuming that the two subsamples (“red” and “blue”) belong to the same selection. Error bars of 3σ are shown.