Oblivion was too bright. However, Morrowind was easily darkened with Gamma. Caves and even night outdoors could go from "Need a torch/lantern/spell to see anything" dark to almost Oblivion bright, but not washed out in a small gamma range. I used to get lost in Vivec at night as I could not find the ramps it was so dark until I adjusted things. With small adjustments of the gamma I could tweak that game to just right where I needed a light to see in some places, but I could see just enough of the cave or area to get the atmosphere of the place.
Note, you have to have your monitor display not at 90% or whatever brightness that is the factory setting or no gamma adjustment will have any real effect.
http://www.imaging-resource.com/ARTS/MONCAL/CALIBRATE.HTM
That is correct and is exactly what I posted about in my reply. My monitors have always been adjusted properly, and both Morrowind and Oblivion were way overbright with no need to bother with any sort of torches or lighting spells. I never, ever had any trouble seeing in Morrowind, not even in Dwemer ruins.
This has always been a problem with Beth games, but they refuse to fix it. That leaves it to modders, but they can only do so much, after all.
Let me put it another way. I find the lighting and various effects in games like Half-Life to be far more believable with exactly the same monitor calibration. Quite amusing, really, if it wasn't so sad.
Here's the real problem: Beth needs to include user optimization so that people can adjust things to suit their specific context. This is what mods such as Realistic Lighting do... so why not the actual developer? It's very silly.