George Eastman developed the first handheld camera in 1988 because he wanted to take pictures of his vacation and needed something lighter to carry and faster to use. He eventually hooked up with Kodak.
In 1850, Allen Pinkerton of the U.S. decided to follow Vidocq's footsteps. He opened up his own Private Investigation Agency. The first in the States.
In the 1860's, Chemical testing started to get lots of techniques, identifying blood, body fluids, and nitrates.
Alphonse Bertillon was the son of an anthropologist. While not interested in being an anthropologist, Bertillon was still influenced by his father's work. He developed a system that measures eleven key parts of the body and identifies the individual by those measurements. It was originally called anthropometry then Bertillage and is now called Bertillon Method. Bertillon used this measurement system at the prison where he worked. The system worked well until he encountered William West. When he took William's measurements, he thought that he already had him in jail. Since escapes were common, Bertillon sent someone to check the cell while he checked his records. Both came back with Will West. Will and William did not know each other but had identical measurements. History shows us that they were identical twins separated at birth. (We are going to come back to this point shortly.)
Within the same time frame, Francis Galton had begun looking a fingerprints. He looked at how China had used them and wanted to study them further. William Hershel was a businessman in India who used fingerprints to seal contracts so he had a large supply of prints that Galton could look at. As Galton was researching his findings, he met Henry Fauld, a doctor who had also noticed ridge patterns and wanted to learn more. Galton developed a system for classifying fingerprints and Fauld offered to set up a system at Scotland Yard. Scotland Yard refused the offer at first then allowed it to be a small addition to Bertillon Method, which had been in use and seemed well proven by then. Juan Vucetich of Argentina had also talked to Galton and Fauld. He liked what he saw and used fingerprints to get a conviction for murder. He then pushed first for Argentina to adopt fingerprints as a stand alone system then pushed for the rest of Europe to follow suit. Edward Henry had also developed a fingerprint identification system that could function on its own. When the Will and William West case occurred, Henry helped to advance his system by showing that Will and William had different fingerprints. This case helped push Bertillon Method out of favor. England started accepting fingerprints as evidence in 1902 to convict a burglar. In 1903, the US started fingerprinting all arrested persons and in 1911, the US courts started accepting fingerprints according to the Frye Standard. (Frye standard states a significant portion of the scientific community must accept new science or evidence before it can be used in courts.)