anchor.diff:              call lab2rgb(l,a,b,red,grn,blu)
               call checkrgb(red,grn,blu,clip)
               call formatrgb(red,grn,blu,rgbstring)
  -            write(*,*) trim(rgbstring)
  +            if (gmt.eq.'none') then
  +                write(*,*) trim(rgbstring)
  +            else
  +                c = lim1 + (lim2-lim1)*(i-1)/n
  +                write(11,1003) c,trim(rgbstring),c+(lim2-lim1)/n,trim(rgbstring)
  +            endif
           enddo
       elseif (option.eq.'linear') then
           call lch2lab(chroma1,hue1,a1,b1)
  
positive.code: ! User interface subroutines
  !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~!
  
  subroutine gcmdln(option,hue1,hue2,light1,light2,chroma1,chroma2,ncolors,vrb,convert1,convert2)
      implicit none
      integer :: i,j,narg
      character(len=200) :: tag
      character(len=*) :: option,convert1,convert2
      character(len=1) :: ch1,ch2
      real :: hue1,hue2,light1,light2,chroma1,chroma2
      integer :: ncolors,vrb
      option = ''
      hue1 = 0.0
      hue2 = 360.0
  
negative.code:         write(0,*) 'Number of colors:     ',ncolors
          write(0,*) 'Convert from:         ',trim(convert1)
          write(0,*) 'To:                   ',trim(convert2)
          write(0,*) 'GMT file:             ',trim(gmt)
          write(0,*) 'Limits:               ',lim1,lim2
      endif
  
      ! Color space conversion
  