Exposure is the amount of aggregate (rock, quartz, pebble etc) that is able to be seen as a result of the grinding process.
Options are nil, random (patchy, salt and pepper) or full exposure (showing as much stone as possible). Full exposure may be susceptible to bull float, screed marks and footprints. Again CCC Polished Concrete can minimize this by involvement with the concreter before and during the laying of the slab.