Grey colors look too dark/black

I've been using my dell u2410 for a few weeks and everything seems fantastic except for one thing that I noticed while watching youtube videos. Dark colors(especially grey colors) look too dark and sometimes I can't make distinction between two close dark colors. How can I make it lighter?

and one more thing. Do colors depend on a graphics card? If I change my old graphics card will the colors be different?

thanks in advance