$\theta_x= -68$and $\theta_y = -6$(helioprojective-Cartesian coordinates), taken at the Swedish 1-meter Solar Telescope [@2003SPIE.4853..341S SST;] [ on September 19, 2016, at 09:31–09:57 UT.]{}

The data was recorded simultaneously by the CHROMIS and CRISP [@2008ApJ...689L..69S] instruments, which observed Fe <span style="font-variant:small-caps;">i</span> 6301 Å, Fe <span style="font-variant:small-caps;">i</span> 6032 Å, [H$\alpha$]{}, Ca <span style="font-variant:small-caps;">ii</span> 8542 Å, and Ca <span style="font-variant:small-caps;">ii</span> K. We only use the latter three spectral lines. The data were processed with the CRISPRED and CHROMISRED pipelines . For a more detailed description of the SST observation we refer to , here it suffices to mention that we obtained near-simultaneous spectral scans in all three lines.

Unfortunately, there is no co-observation with the Interface Region Imaging Spectrograph [IRIS @2014SoPh..289.2733D]. Therefore, we use IRIS data observed on February 5, 2016, at 08:21–09:12 UT in order to be able to compare our computations of the [k]{} line. The IRIS target is an emerging active region NOAA 12494, observed near the disk center at $\theta_x =  -96$and $\theta_y = -98$.

Figure \[fig:observations\] shows the line core images for all four spectral lines. Panels a-c show an active region covered with fibrils and a sunspot in the upper right corner. Panel d shows a slit 