Segundo de Chomón, as a rule, was not a documentarian. In his early years, he had shot documentaries of cities in Spain to release to the French audiences in France, and in later years--from 1911 to 1912--he would once again resume this documentary work; but in between these times, from 1905-1909, he was a voracious trick film director, specializing in elaborating on the films and ideas of his competition, Georges Méliès. These trick films took up the majority of his work as a film director, and typically they are now what he is known for; and while documentation was a pastime of his, it was not his significant part in the development of filmmaking. Thus, "The Express Sculptor" is very much different from the work he was turning out at this point in history, and remains somewhat standout because of this.
While the other reviewer claims that the short is indeed a gimmick film like the rest of the work Chomón was working on at this time, it is quite apparent the entire work is purely a documentation. It captures a professional sculptor at work making clay faces, along with the help of an assistant. The sculptor was Lee Yost, and while forgotten today it is clear he had plenty of talent. The works of art on display are both comedic and well done, and it's particularly enjoyable when Yost punches in the faces he makes and wrecks them. For a documentary, it is not bland and is quite enjoyable despite lack of any sort of story.
It puzzles me that IMDb and all the other sites claim Julienne Mathieu, Chomón's wife, was the sculptor's assistant. Mathieu was an actress at Pathé Frères and clearly not an assistant to the sculptor, in which case she would have worked with him professionally. If it is true that she participated in the film, then clearly the job was a fairly simple one devoid of any talent. As it is, for 1907 this was very well made. The short incorporates both closeups and medium closeups, as well as starting off with a long shot. This technique of cutting between viewpoints was not only revolutionary, it also shows how Chomón was learning how to become his own filmmaker. This short was clearly deserving of this type of cutting, and it forced the director to do it to the point where he began to discover how closeups can make scenes more effective--or in the case of a trick film, make illusions more effective. In 1907 he was still copying his competition; it was in 1908 that he would finally put closeups to use in his trick films.
The simple magic trick at the beginning, which was indeed created through film editing, makes it clear you're watching a Chomón short, however--especially because the two bowing simulates a magician and his assistant. No matter how documentary this is, it has a groundbreaking early use of cutting and closeups and uses some humor and a few nice touches to make an entertaining work. Enjoyable.