Welcome to the AVS forum. Your picture is controled by a number of things number 1 is how you go with lighting. Press menu go to persoanal preferences, choose anyone but *personal* and you'll have a bighter picture.
I use personal because my inputs have memory. I own a RCA F38310,the second factor is warmth on cool your picture will be more bluer, on medium to high you get more red. Lastly on the indivual movies your watching on vhs turn your contrast and your sharpness down, and cotrol your picture with the blacklevel.
DVD turn your contrast up a bit more, your sharpness up about 1/6, and use yur blacklevel to control your brightness. Try each warmth out for your own personal preference. I don't have night blindness at all because I take what worked for R.A.F. pilots in W.W.2
Last of all don't be afraid to experiment it isn't going to bite you!