HMI Continuum images (top) and LOS magnetograms (bottom) showing the evolution of active region NOAA 12317 from 17:00 UT on 2015 April 1 (left) to 17:00 UT on 2015 April 3 (right). The FOV covers 150″  ×  150″, and the coordinates in the lower left corners refer to the FOV’s center. The black solid squares in the left panels correspond to an ROI of 30″  ×  30″, which is used in the analysis of the high-resolution Hα and TiO time series. Dashed squares correspond to an ROI of 95″  ×  95″ which is used in the determination of the photometric area and magnetic flux shown in Fig. 6. An arrow in second-lower panel indicates the negative polarity pore belonging to the secondary flux system. Magnetograms are displayed in the range ±400 G. An animated version of this figure is available online.