int im_Lab2UCS(in, out)
IMAGE *in, *out;
int im_LabQ2XYZ(in, out)
IMAGE *in, *out;
int im_UCS2Lab(in, out)
IMAGE *in, *out;
int im_Lab2disp(in, out, display)
IMAGE *in, *out;
struct im_col_display *display;
int im_disp2Lab(in, out, display)
IMAGE *in, *out;
struct im_col_display *display;
int im_UCS2XYZ(in, out)
IMAGE *in, *out;
int im_XYZ2UCS(in, out)
IMAGE *in, *out;
im_Lab2UCS(3), for example, is defined as:
  int
  im_Lab2UCS( IMAGE *in, IMAGE *out )
  {
     IMAGE *t1 = im_open_local( out, 
        "im_Lab2UCS intermediate", "p" );
   
     if( !t1 || 
        im_Lab2LCh( in, t1 ) || 
        im_LCh2UCS( t1, out ) )
        return( -1 );
   
     return( 0 );
  }