Robert Cornelius (; March 1, 1809 – August 10, 1893) was an American photographer and pioneer in the history of photography. He designed the photographic plate for the first photograph taken in the United States, an image of Central High School taken by Joseph Saxton in 1839. His self image taken in 1839 is the first known photographic portrait of a person taken in the United States. He operated two of the earliest photography studios in the United States between 1841 and 1843 and implemented innovative techniques to significantly reduce the exposure time required for portraits. He was an inventor, businessman and lamp manufacturer. He created and patented the "solar lamp" in 1843 which burned brighter and allowed for the use of cheaper lard as a fuel source rather than more expensive whale oil. Early life and career Cornelius was born in Philadelphia to Sarah Cornelius () and Christian Cornelius. His father immigrated from Amsterdam in 1783 and worked as a silversmith before opening a lamp-manufacturing company. He attended private school as a youth and took a particular interest in chemistry. In 1831, he began working for his father and specialized in silver plating and metal polishing. Soon after the daguerreotype was invented, Cornelius was approached by Joseph Saxton to create a silver plate for his daguerreotype of Central High School in Philadelphia. Saxton's photo is believed to be the oldest photograph taken in the United States. It was this meeting that sparked Cornelius's interest in photography. Self-portrait With his own knowledge of chemistry and metallurgy, as well as the help of chemist Paul Beck Goddard, Cornelius attempted to perfect the daguerreotype. Around October 1839, at age 30, Cornelius took a self-portrait outside the family store. The daguerreotype produced is an off-center portrait of himself with crossed arms and tousled hair. While Louis Daguerre's photograph of the Boulevard du Temple, taken one year earlier, incidentally included two people on the sidewalk, Cornelius' photo is the oldest known intentional photographic portrait of a person made in the United States. It was preceded by at least some months by portraits taken by Hippolyte Bayard in France. The quality of the photographic plate and the technique used required him to sit motionless for 10 to 15 minutes. Cornelius did not make much of his achievement of the first human photograph in the United States. It survived due to the efforts of Marcus Aurelius