I'm making timelapse recordings on a confocal microscope, but I'm having some difficulty deciding how to normalize the data. For each culture, I recorded a full timelapse with no interference on my part (the none video). I next recorded a timelapse where I began my treatment on frame 10. Would I be better off normalizing all of the data to the none video? Or should I normalize the data in frames 11-100 to the data in frames 1-9?