Are you aware of how little light you need to see? Just because you assume the light in the video is similar to a 40w bulb is short sighted (no pun intended). A 2W "pretty dim" incandescent bulb will illuminate a room no problem.
Human eyes can adjust very well to low light levels.
It depends on what you're trying to do. For just minimal seeing, yes. For reading, or many kinds of tasks, not so much. There's not enough in the article to know for sure how they're pitching it to the people that might actually use it.
I once done a stint in the military, and during training we had to use red light at very low levels to read and write at night time .. it is possible, just a world away from what the average human with access to electricity on tap is used to, I guess.
Yes, you're right, I remember similar things from my time in the Navy. This kind of lighting regime is normal in the combat spaces of a ship, even in the daytime.
The GravityLight article does say that it's meant to replace kerosene lamps, which according to Wikipedia range from 20 to 100 lumens:
This is about the equivalent of a 1.6 W to 8 W incandescent bulb, so you're right, I was too quick to dismiss the numbers as being too low. They're certainly low compared to what first world citizens are used to, but they are roughly equivalent to what the target users are used to.
Considering the goal is 55k, and that the basic principle is sound and surely can be improved in efficiency, I have to say reading this discussion and the jaded way people just dismiss it wholesale as "hoax", and not give a second thought is kinda shameful indeed.
Kickstarter is overflowing with game projects raking in the millions collectively with unverifiable claims altogether, like "awesome multiplayer experience". But this stuff? "It's a hoax, they're trying to rip the public off for 55k!" You simply cannot make this shit up.
Human eyes can adjust very well to low light levels.