The version of the Jurassic Park scan that was released is a quick-and-dirty rough version. I believe the LUT was set to adjust black levels to pure black. The digital video codecs we use still have a narrower dynamic range than film (even at 0-255), and film doesn't actually project black as absolutely pure black (even, I assume, on stuff like IB Tech and silver retention that I've heard have deeper blacks than other prints). So it probably wasn't that dark in theaters. Or at least, you could probably see what was going on better than in those images.

PDB, DoomBot, are either of you here? I know this thread isn't about the JP preservation, but can you weigh in? Is there lost shadow detail compared to the flat scan?