After using a couple of different filters im kinda confused about infra red pollution filters. I have used a set of Tiffen irnd which were a little bit greenish then i've used another set which had a slight magenta on it. Whats the difference? I dont get it. And then there is this another issue about the filter called 'hot mirror'. When do i have to use it? Some people say that even if i use irnds i should use it. A couple of days ago i've seen another filter from tiffen called 'T1' what is that? Is it another type of hot mirror? So im really confused guys help me out. Which filter does what and do i have to white balance after i put them in front of the lens?