The catalogues may have recorded a patent applied for in the previous year. A patent applied for in December may have been granted (with an official number) in January of the following year. There may be other circumstances as well. The only way to be certain of a date is to refer to the patent's contents but as a rule there was never more than one year between the filing of the patent application and the date when it was granted. The important reference is the patent number. A few patents don't have a number. For those, you need the year, the name and the title in order to access the microforms at the Institut National de la Propriété Industrielle (I.N.P.I. Paris). Patents between 1812 and 1838 may not be exactly "photographic" but will be of interest to those who study the origins of photography. Those beyond 1920 may be found browsing http://www.inpi.fr.
© Constantin IMBS February 2007 |
