An article titled “How to Make Spirit Photographs” from the August 25th, 1916 edition of South Side Signal.
This article explains how to make spirit photographs by printing from regular negatives onto printing-out paper, fixing the prints in a hyposulphite of soda solution, and then immersing them in a bichloride of mercury solution. To reveal the spirit photograph, moisten a piece of blotting paper and hold it in contact with the print.