of visible light, made this data set an ideal source to carry out a systematic search for visible-light flares. HMI continuously observes the full disc of the Sun in a FeI (617.3 nm) line, which is scanned at six positions throughout the line profile. From these six filtergrams, the pseudo-continuum images $I_{\rm c}$ (together with an estimate of the line depth and line width and also and estimate for the Doppler velocity and line-of-sight magnetogram) are reconstructed by a technique described by [@2012SoPh..278..217C]. The algorithm used is known to perform poorly in magnetised regions [e.g. @2015SoPh..290..689C], but estimates of line depth and continuum intensity seem not to suffer too much from algorithm artefacts. Let us keep the discussion about the actual origin of the emission recorded in $I_{\rm c}$ images for later and assume that $I_{\rm c}$ images can be used to systematically investigate appearance of WLFs.

The HMI instrument was used for investigation of individual solar flares recently [e.g. @2011SoPh..269..269M], where the authors investigated the flare appearance in all six filtergrams used to compute the line-of-sight quantities. They found e.g. a suspicious behaviour of the derived Doppler velocity in the presence of the flares, which was later re-investigated [@2014SoPh..289..809M]. 