Something that neither reflects nor emits light is by definition invisible. If a camera can’t record it then you can’t see it. Generally, most people who believe in ghost encounters believe you can see them (that’s how you know it’s a ghost).
Actually, no. You perceive the ghost and you may experience that as seeing it, but someone standing next to you doesn’t see it because, hey, it’s not material; it can’t be seen.
This isn’t a novel idea; it’s how Shakespeare, for example, treats the ghost of Hamlet’s father. We know the ghost is a ghost because only Hamlet perceives it. If it reflected or emitted light, everybody would see it.
You guys are arguing about the correct rules that apply to a made-up thing? Good luck winning that one.
So it’s like a psychic phenomenon. I understand.
It seems like the fad now is to treat ghosts as a physical phenomenon, which can be recorded physically through audio and video (at least through EVP), that you can measure electromagnetic energy and/or heat changes (“cold spots”), and so on. Hence shows like Ghost Hunters, Ghost Adventures, etc. The people advocating these photos subscribe to this school of thought.
Then there are psychics that can sense/hear/see/channel ghosts that others can’t detect. That school of thought is still popular, and sometimes these people will accompany the “ghost hunters” using technology to look for ghosts.
I’m waiting for the leprechaun fad to start. I want to see documentary shows where people look for tiny Irish people using infrared cameras and psychics, to find their gold. I’d watch that.
Locate it in the Auld Sod, and have every episode end in a pub for a wee dram.
Even the rules applying to made-up things need to be coherent! (In fact, especially the rules applying to made-up things need to be coherent.)
An unspoken and unacknowledged philosophical assumption that underpins much of modern culture is materialism - the belief that only material things are truly real. Thus, if spirits are truly real, they must in fact be at least a little bit material and so we can detect them with cameras and sound recording and all the paraphernalia of the scientific investigation of the natural world.
The inherent contradiction here is that if something is a little bit material then it’s to the same extent a little bit not spiritual. If you truly believe in the reality of the spiritual, then you’ll reckon that trying to photograph spirits makes about as much sense as trying to photograph justice or truth. And, if you’re trying to photograph spirits, or are hawking around photographs which you think are or may be photographs of spirits, then what you believe in are not really spirits at all. They are material phenomena.