Generally during the day I film without lights and with the red filter in place. Each shot is white balanced electronically using Amphibico's white balance chart. This does not always produce perfect results since the distance from the lens to the white balance chart and from the lens to the subject may be different or the sun can go behind a cloud affecting the amount of available light or the subject moves thereby changing your angle to the light. Some colour balancing in post can rectify minor adjustment requirements.