Taking photographs at seances had become popular in 1940. At these seances mediums would deliberately try to evoke spirits of the dead for communication. Infra-red devices were usually used here because most seances took place in total darkness, normal photography was near on impossible.
Of course, hoaxes have been exposed over the years, however, some images that were taken during seances did look very interesting. Ectoplasm, I feel, is the most interesting.
Ectoplasm is known as a strange, white dough-like substance that would extrude from the mouth, nose or even the naval or certain mediums. This incident had been filmed more than once. It was thought to be used by spirits as a substance to mould a temporary physical presence on earth. Sceptics would often shout fraud, alleging it to be some sort of cloth, stuffed into the mouth of the medium.
During the 1940s, photographic techniques were improving and those guilty of fraud were soon found out due to their reluctance to let camera in. On the other hand, those who were sincere were happy and eager to provide hard evidence that life after death is certain.
Although some might scoff, those who have lost a love one would surely believe. The motivation to believe in the survival of the soul after death is irresistible.