What is wrong with a big screen tv if the picture seems dark?

Probably nothing. Your seeting may just need to be adjusted. You may need the TV Calibrated. A calibration is performed by a trained technician. They put a DVD in your DVD player which puts different color hues. They stick a sensor to the screen of your TV which is connected to a laptop. The sensor reads the light level in the room and takes snapshots of the TV picture and tells the tech what to change all of your settings to to get the best picture in the room the TV is used in. A TV calibration can be purchased at the following retailers: Circuit City - $150 Best Buy - $300