Well, the actual number of companies that produce the sensors on cameras are very few and far between and mostly under strict control and protections.

They apply special filters (ie chemical treatments and etching) to different sensors and they need to design them for specific colours and response curves.

They can cut out select frequencies using an inverted band-pass filter and let’s hypothesize that ghosts exist in a spectral wave range….maybe just maybe these days they are expressly and secretively required to exclude certain bands.

Just like how select RF is illegal to transmit on or listen to. You have you manufacture your own devices or modify them illegally to hear or speak on those bands