To demonstrate how humidity can create false orbs in ghost photographs, I took these photos at dawn on a dark, damp morning standing on a bridge. A stream flowed under the bridge from a large pond.
In addition, light rain was falling.
[...]

False “ghost orbs” occur in humidity. We’ve shown that on our Ghost Hunters Guide pages, These are not ghost orbs and This is Not a Ghost Portal. However, some people think that rain should photograph as lines, not orbs. [...]

Ghost orbs can be one of the most reliable ways to tell if something odd is going on at a site that’s supposed to be haunted. However, all ghost hunters must be cautious about calling something a “ghost orb” when humidity is present.
[...]

On Friday, 10 May 2002, Fiona Broome taught a class in Ghost Photography at LightLines, in Portsmouth, NH. After an hour of basic instruction, the class went outside to take pictures.
The evening was somewhat windy, but otherwise dry and bugfree. The cemetery is near houses, [...]

We wish we could say that these nice, clear orbs are evidence of ghosts. In this photo, the night looks clear, the wall in the foreground appears crisp (even in ISO 800 film), and so on.
Unfortunately, this picture was taken earlier on the same night as the This [...]

This is NOT a portal, hundreds of orbs, or a ghostly mist… This photo is not evidence of a haunting. We’d love to claim those are a bazillion orbs, coming and going through a portal in this haunted cemetery. This is a photo taken on a very misty [...]