the $rgb value is being generated based on C_MIN and C_MAX constants.
So, if you want have one specific color (actualy brighnes), then set these constants to the same value.
or if you wish, you can specify different color for all letters by replacing $rgb with a number (0 - 255):[qcode]$color = ImageColorAllocate($im, red, green[/i], blue);[/qcode]