Hi Fred
Heres a thought for you.
If you want to check if your ir tv remote is working, take your cell phone camera which doesnt have i/r blocking (or so i an led to believe) and focus on the led of the remote. when you activate the remote, if it is working you will see the cell phone camera responding to the ir.
Now use the cell phone camera with the tv remote and insert the filter in between. this should give you some idea of whether the filter passes ir or not.
Am not to sure of the wavelength of the tv remote but should be well into near ir
Worth a try???