100% black text window

[Cap_]

I'm looking for a way to make the text window completely black. Every time I set all the colors to -255 the window still has background lines and it's slightly transparent.

 

[Tw0Face]

#===========================================================================
# Window Color Opacity - v1.0
# Author: Melkino
#===========================================================================

$imported = {} if $imported.nil?
$imported["MK-WindowOpacity"] = true

#-------------------------------------------------------------------------
# ▼ About
#-------------------------------------------------------------------------
# This script lets you change the opacity of the colored portion of game
# windows. Window borders are unaffected, though.
#
#-------------------------------------------------------------------------
# ▼ Installation
#-------------------------------------------------------------------------
# Paste below Materials and above Main.
#
#-------------------------------------------------------------------------
# ▼ Updates
#-------------------------------------------------------------------------
# May 9, 2012 - Started & finished script
#
#-------------------------------------------------------------------------

class Window_Base < Window

module MK_WIN_OPA
 
    # Input a value between 0-255.
    # 0 makes windows fully transparent, while 255 makes them opaque.
    OPACITY = 255
 
end #module
 
#===========================================================================
#  Customization ends here.
#===========================================================================

  #--------------------------------------------------------------------------
  # * Object Initialization
  #--------------------------------------------------------------------------
 
  alias mk_initialize initialize
  def initialize(x, y, width, height)
    super
    self.windowskin = Cache.system("Window")
    self.back_opacity = MK_WIN_OPA::OPACITY
    update_padding
    update_tone
    create_contents
    @opening = @closing = false
  end
 
end # class

 

[Andar]

Every time I set all the colors to -255

you don't set the color to -255, you set a tint to -255.

color codes are between 0 and 255 only, it is absolutely impossible to have a color with a negative value.
tinting is a mathematical operation of adding a value to a color to calculate a new color. That is why you can add a negative number to a color code to reduce that color code, but it will never go below 0. (0,0,0 is the RGB color code for black).

If you get something other than black after tinting with -255, then you have another color mathematic operation elsewhere to add to the original color, and if that other operation has a higher priority, then the -255 can be overridden.

If using the code above does not work, you need to find that other color influence and reduce it, and to help you with that we would have to know where you did what.