However, William Mumler certainly did allow a great number of skeptics as well as photographic experts (who surely would of been aware of the tricks used to create fake ghostly images) to examine the process from start to finish and to inspect his equipment and people were unable to find evidence of fraud.
A professional photographer at the time named Mr. Jeremiah Gurney had this to say about William Mumler's photography:
"I have been a photographer for twenty-eight years; I have witnessed Mumler's process, and although I went prepared to scrutinize everything, I could find nothing which savoured of fraud or trickery. The only thing out of the usual routine being the fact that the operator kept his hand on the camera."
Despite this and many other supporters, there were ongoing accusations against Mumler including the accusation that Mumler would break into peoples homes in order to obtain photographs of deceased relatives which he could then use to create fake spirit photography. It was also stated that some of the "spirits" appearing in Mumlers photographs were recognised as living persons. These accusations eventually amounted to Mumler being taken to court charged with fraud in 1869.
Barnum felt that William Mumler was making profits by taking advantage of people at a time when they were unable to think clearly due to the grief they were experiencing after the loss of a loved one.
A selection of photograph's taken by William H. Mumler
Above: Perhaps one of the most famous photograph's taken by Mumler, this photograph shows Mary Todd Lincoln sitting with the spirit of her deceased husband Abraham Lincoln standing behind her. According to reports, William Mumler was not aware of Mary Lincolns identity before the photo was taken, as she had given a false identity by the name "Mrs. Tundall" and she turned up with her face almost completely covered wearing a black hooded robe and asked that she only reveal her face at the exact moment the photo was taken. As the photo developed, it revealed Abraham Lincoln himself to be the spirit "extra".
Above: There is a truly remarkable story behind this picture of Moses A. Dow. Read his testimony by clicking here. According to his own testimony, he had managed to make contact through spiritualist mediums with a deceased young girl who he once employed to work for him. She informed him that should he visit a spirit photographer, that she would make an appearance and also gave details as to what position she would take, what she would wear ect. William Mumler took the photograph, as far as I am aware with no prior knowledge of this and Dow even assumed a false identity. Needless to say the image produced a spirit "extra" of the exact description and likeness of the girl who Dow had been in contact with.