Interesting recent research on the early colour daguerreotypes of Levi Hill, dating from around 1850.
In the past it had never been conclusive as to whether Hill's colour daguerreotype process was authentic or not. It now seems that although he may have added some colours to enhance the photographs - especially in the areas of colour where they were weak in order to promote the process - that in fact the daguerreotypes do indeed contain authentic natural colours inherent to the process. And that Hills work is most likely some of the first colour photography.
I also find it interesting that the Hills process was so threatening to the photographic status quo of the day that photographers threatened to smash up his studio and actually succeeded in suppressing his publications...