profile/iccvcgt
    Summary
    Extract or insert 'vcgt' calibration tag from/into ICC profile.
    Usage Summary
    usage: -x profile.icm
        curves.cal
        usage: -i inprofile.icm curves.cal outprofile.icm
         -v             
        Verbose mode
         -x             
        Extract 'vcgt'
         -i             
        Insert 'vcgt'
    Usage Details and Discussion
    
    The -v flag may give extra information.