The filter is not removable – you either get it with the UV filter or without. Basically the device (spectrophotometer) “sees” optical brighteners differently than we humans do - where we see white, it sees blue. The problem with that is the spectro/software overcompensates and adds yellow to counteract the blue, which results in a yellowish-looking print. There are various ways to get around this problem (and lots of debate), but a simple solution is to just get the UV version of the device since it blocks the wavelengths that cause the problem in the first place. Note that both the i1Basic and i1Xtreme come in both UV and non-UV “flavors”. As for scanning before or after lamination, it’s usually best to measure the media with the finishing (laminate) applied, since that’s how it will ultimately be shown.