Symptoms

This is a lighting error: the SKY looks lit but some models, especially the player's weapons, are dark.

Causes

• The floor is func_walled or the player is clipped way above the floor somehow (elevator?)
• Bad light environment settings (the PITCH should be negative "-" to shine DOWN)
• SKY walls on the side of a level are too low on the horizon
• With a spotlight, the "pitch yaw roll" value isn't the same as the "angle" and "pitch"
• Other.

Explanation

Models take their brightness & color value from the brightness & color of the floor below them so if the floor is dark, far away, or black color, any model above it will be black too. Having them on a bright brush entity doesn't count.