a brief rant
The aim to make your tv series appear "dark" or "edgy" or "gritty" or whatever does not mean that the screen has to be literally too dark to make out anything. I get that there are mood lighting choices, and atmosphere through colors and so on, but it completely defeats any kind of purpose if your viewer can't see or follow what's going on. It is not all that sinister if you have to squint and guess what is happening. Seriously, things can be dark and edgy even if there is a lightsource somewhere! (This was brought on by me trying to watch SGU, but really it applies to a lot of series.)