putty to change screen colours

Can any one tell me how to change the screen colors of the screen when connected unix using putty. I tryed setting from colors but it's not happening

faq-colours

or
putty man page

Right click on the top bar
Left (or right) click on "Change Settings"
Click on one of the selection in the:
"Select a colour to adjust"
Enter RGB values (0-255)
click "Apply"