The alleged spirit of William Barrett

Paranormal investigators sought to expose Hope as a fraud in 1922 Hope was later exposed as a fraud in February 1922; paranormal investigator Harry Price went so far as to write in a report that: "William Hope has been found guilty of deliberately substituting his own [photographic] plates for those of a sitter... It implies that the medium brings to the sitting a duplicate slide and faked plates for fraudulent purposes."
In other words, Hope used multiple exposure techniques to add ghostly spirits to photos.
Hope's followers and fanbase remained loyal and even claimed to spot the controversial photographer's ghost in photos after his death.