content: set MIN_VALUE to 64
  set MAX_VALUE to 255
  set STEP_SIZE to 30
  
  set RED_FACTOR   to 1.0
  set GREEN_FACTOR to 0.635
  set BLUE_FACTOR  to 0.295
  
  on brighter(brightness)
      global MAX_VALUE, STEP_SIZE
      set brightness to brightness + STEP_SIZE
      if brightness > MAX_VALUE then
          set brightness to MAX_VALUE
      end if
      return brightness
  end brighter
  
  on darker(brightness)
      global MIN_VALUE, STEP_SIZE
      set brightness to brightness - STEP_SIZE
      if brightness < MIN_VALUE then
          set brightness to MIN_VALUE
      end if
      return brightness
  end darker
  
  tell application "DarkAdapted"
      set rgb to getGamma
  end tell
  
  set oldDelimiters to AppleScript's text item delimiters
  set AppleScript's text item delimiters to ","
  set rgb to every text item of rgb
  set AppleScript's text item delimiters to oldDelimiters
  
  set red   to (item 1 of rgb as integer)
  set green to (item 2 of rgb as integer)
  set blue  to (item 3 of rgb as integer)
  
  # log "old rgb = " & red & "," & green & "," & blue
  
  set brightness to brighter(red)
  # set brightness to darker(red)
  
  set red   to (brightness * RED_FACTOR)   as integer
  set green to (brightness * GREEN_FACTOR) as integer
  set blue  to (brightness * BLUE_FACTOR)  as integer
  
  set newrgb to "" & red & "," & green & "," & blue
  
  # log "new rgb = " & newrgb
  
  tell application "DarkAdapted"
      setGamma value newrgb
  end tell
  