Both Filmic and Sigmoid are tone-mappers. Their job is to map the linear, scene-referred data to non-linear, display-referred data that your monitor (or print medium) can display correctly. They just do it in slightly different ways, providing different trade-offs.
Since it makes no sense to tone-map twice, only one tone-mapping module should ever be active.
If you don’t understand the scene-referred workflow and the role tone-mappers such as Filmic and Sigmoid play, I highly recommend the following:
