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tokens: caused by the erupting filament plasma and the bright ribbon fronts on the outer border of the growing dimming region that come into the pixel’s FOV. Figure 7. Time evolution of the relative density changes, i.e., actual density divided by its pre-event value, derived from AIA DEM maps for pixels corresponding to the EIS spectra in Figure 6 . The segments in red indicate the phase of the impulsive density drop: its start is defined by the data steeply decreasing below 1, and its end is calculated from the time derivative of the curve (defined by the first positive increase). The green vertical lines indicate the time at which the corresponding pixel was covered by the EIS slit. To relate the evolution of the densities reconstructed from the AIA DEM maps (Figure 7 ) in the 4 pixels indicated in Figure 5 with the corresponding spectra and flows determined from the EIS scan (Figure 6 ), we need to relate the dynamics observed in AIA with the time at which the EIS slit covered the particular pixels. We first discuss the behavior of the top three pixels plotted in Figure 7 , and thereafter the bottom-most one, which is related to different structures as we will show. In the density evolution retrieved from the DEM maps (Figure 7 ), we can see that the sharp density drop due to the dimming occurs first in the leftmost (easternmost) pixel, and thereafter in the two neighboring pixels to the right. This is consistent with the expansion of the dimming region toward the west, i.e., from left to right (see Figure 8 and the associated movie). On the other hand, EIS was in scanning mode, and we may expect to see the largest upflow components in those pixels that have been activated as dimming pixels (i.e., the associated fields were “opened”) closest in time to when the EIS slit was mapping them. Figure 8. Evolution of the western dimming region in SDO /AIA 211 Å filtergrams. We show the same zoomed FOV as for the EIS maps in Figure 5 . The yellow boxes mark pixels for which we show the EIS spectral profiles in Figure 6 . The still figure shows the event at two time steps (annotated in each panel). The animated figure shows the event evolution from 2012 September 27, 23:50 UT to September 30, 01:16 UT. (An animation of this figure is available.) The EIS scan was from west to east, and the strongest upflow component is observed at the pixel ( x = 563′′, y = 44′′), which was covered by the slit at 00:04:16 UT. This is the pixel where we find that the total amount of upflowing plasma is larger than the stationary plasma component. The AIA density evolution shows that in this pixel, the strong drop in the density, indicative of the impulsive dimming onset, starts exactly at that time when it was mapped by the EIS slit. In the neighboring EIS pixel to the left, centered at x = 560′′, the impulsive density drop occurred during 23:58 to 00:06 UT, and the EIS slit covered it during this time range at 00:04:58 UT. This finding is consistent with EIS still showing a