Qustion about Extractions

Does anyone know if the extracting process happens on a film for the IGI do they extract everything or certain records? or just some? My working on my camino line and it appears they come from Pinos, Zac. but there is only one family listed in Pinos at the time frame. 1790's. All caminos so far on IGI come from Jose Camino and Gertrudis Fernandez de Villapando in Pinos on the IGI. Any help? Thanks!-Daniel Mendez del Camino