Dear Kurt,
Glad to make a friend with you! This is David
IR Cut use the double filter to suit the D&N requirement.
IR Camera will loose the natural color, it is the shortage of the IR Camera; and B&W camera can get the natural color in the day , but it can not see in the low illumination condition. In the day the common filter to cut the infrared light and get the natural color. While the illumination is lower enough, it will turn to the other filter(ICF), it can cut most of the visible light and change to the B&W situation to support the totally night-see function. So it can get the pure and natural color in the day and more clear in the night.
ICR is the same meaning, but professional express way is IR Cut.
If you have any promble ,PLs let me know . Hope I can answer it for you.