Example of the evolution of a PMJ whose brightening is observed during three frames (lifetime of 51 s) in the inner limb-side penumbra (labeled as PMJ 1 in Fig. 1). Left: continuum intensity images at +2.4 Å from the line core. Center: blue-wing images, at −0.3 Å from the core. Right: blue-wing intensity difference images with respect to the frame recorded 17 s before. Time increases from top to bottom, see labels on the right panels. Middle row: maximum brightness stage. Black contours delimit the PMJ area, that is, the region displaying blue-wing brightness enhancements larger than 10%. White dashed contours enclose the CC, defined as the region displaying a line-core brightness enhancement larger than 10%. White solid lines delimit the inner penumbral boundary. Black arrows indicate three penumbral filaments and a bright grain observed in the continuum images near the brightening region.