LUT

        [GTVL\]LUT Argum [/PEN]

    Modify the bitmap or pen look up table. Option /PEN indicates to  modify
    the  the  value  of  the  16 user-controlled pen colors (colors 8 to 23)
    rather than the bitmap look-up table.

    Possibles arguments are:
      - COLOR Load a default color table
      - WHITE Load a black and white color table  (White  background,  black
        sources)
      - BLACK Load a black and white color table  (Black  background,  white
        sources).
      - LUT Load the color table defined by an HSV color model. (HSV  stands
        for  HUE,  SATURATION and VALUE). There are three user-writeable SIC
        Variables of name HUE, SATURATION and VALUE, that  contain  the  HSV
        model  of  the  current LUT. These array's values can be manipulated
        using standard SIC mathematic functions to create new Lookup  Tables
        (see below).
      - Any other : "LUT Argum" will read Red Green  Blue  values  from  the
        formatted file named "Argum".

    The default argument is LUT. A convenient value for the HUE array is
      LET HUE[I] = 256-2*I !a "classical" color table from blue  to  red  as
        used in AIPS for example.
        Color contours can be obtained using variations around the following
        command:
      LET HUE[I] = 16*INT((256-2*I)|16)
        and so on with the most funny functions you may invent.
    CAUTION : the HUE is a real number between 0 and 360.0

    Note that a similar behaviour is defined for the  pen  colors  with  the
    arrays  P_HUE,  P_SATURATION  and P_VALUE (the colors of the 16 contour-
    filling pens), and for the BLANKING  color  (the  color  used  to  paint
    blanked  pixels  in  images),  with  the 3 reals B_HUE, B_SATURATION and
    B_VALUE.