The so-called recording ghost is one which seems to do the same thing each time it is witnessed. These ghosts tend to get reported in 'faction' books, ie. those that are 'fact' but which often rely on second or third-hand reports. In 'real' cases (ie. those carefully investigated and well-reported by experienced researchers), such 'recordings' are surprisingly rare. More often, a case just consists of a number of strange noises, odd sightings and other strange occurences. Though these things often happen in the same places within a house ('hot spots') they are rarely exactly the same each time they are witnessed. The case for recording ghosts is a lot weaker than casual readers of ghost books might think.
The 'hot spots' in haunted locations are often associated with unusual natural phenomena such as creaky floor boards or bizarre (but natural) shadows. They produce similar ghostly reports because they are produced by the same natural phenomena.
Consider the example at the start of this post. A strange shadow might be cast by headlights from a passing car outside. As the car moves so the shadow moves, perhaps resembling a moving figure. The 'ghost' would only appear when a witness was in the correct position at the bottom of the stairs as a car passed outside. It might only happen if the curtains were not closed. So the 'ghost' would only appear rarely and each time 'it' would appear to do the same thing. Investigators might never see the 'ghost' unless they stood in the correct spot with the curtains open and waited for long enough.
So, not only is the case evidence for recording ghosts weak, but those that do apparently occur can often be explained by completely natural events. So why are researchers so keen on the idea of recording ghosts?
If recording ghosts were real they would be amazing! They would be a recording made somehow (no one has yet come up with any plausible way for this to happen) of an historical event. Far better than a photo, they would allow us to see exactly what things looked like in the past. There might even be important historical events frozen in these recordings. However, this raises an interesting question. If they ARE recordings, why do we only see a figure? Why can't we see the background around the figure too? When you take a photo of a person you see the figure against a background. So where IS that background? It's a very odd type of recording!