Winters are dark, in case you were wondering. As of now, there is a experimental patch online that tweaks light values to be more in line what the SRD claims darkvision, low-light vision and human vision is like.
Things may seem very dark at the start; however, that is intended. The baseline I chose was for areas with no light at all - a moonless, colourless, lightless void. Humans see about 1 meter, low-light is two, with a nice hue to it; and darkvision is blue-ish (to simulate greyscale which cannot be done with the nwn1 lighting engine)! There is only one type of darkvision for now, and as a compromise I've set it at about 90ft (2-ish tiles) to accomodate both the 60ies and 120ies.
Having a proper zero-baseline means that area creators have a much wider creativity range with area lighting, and the weather system can adjust area lighting to match moon phaseeventually; but this will also mean that torches and other light sources are actually much more useful because noone likes to run into things. Please don't tweak area lighting yet to accomodate the new lighting scheme. It is experimental, after all.
As a side-effect, Ultravision (that garish pink effect) is now gone and replaced with the exact same visuals as darkvision itself, so the spell works again as intended by Ao. Or something.
For the curious, the patch in question is fx_light_clr.mdl in silm_merge.hak.