jaw-image at the nominal line center of  k, of an active region with one sunspot located on the left side and a sunspot outside the FOV on the right side. Long elongated fibrils are connected with the sunspots and pores located in the middle of the FOV.

Results {#sec:results}
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The effect of non-LTE electron density on the emergent intensity {#sec:ccem}
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We compared how different are electron densities computed either using the LTE equation-of-state for all chemical species or by treating hydrogen in non-LTE with imposed conservation of charge. We found severe differences between the LTE and non-LTE values in the middle and upper chromosphere.

On average the [inclusion of]{} charge conservation [in the calculations,]{} leads to higher electron densities [compared to LTE]{} in cold areas of the chromosphere, owing to an increased hydrogen ionization degree through the Balmer continuum. This difference was largest (by a factor $\sim 10^3$) in cold pockets [(3250 K)]{} right below the transition region. [In hot areas in the mid chromosphere we typically find a somewhat lower electron density than in LTE.]{} Figure \[fig:nlte\_lte\_edens\] illustrates how the non-LTE electron densities change the emergent intensity in  k. For the spatially-averaged intensity, the maximum relative difference 