who developed an explanation for the photoelectric effect
Photoelectric effect In 1887, Heinrich Hertz[2][3] discovered that electrodes illuminated with ultraviolet light create electric sparks more easily. In 1900, while studying black-body radiation, the German physicist Max Planck suggested that the energy carried by electromagnetic waves could only be released in "packets" of energy. In 1905, Albert Einstein published a paper advancing the hypothesis that light energy is carried in discrete quantized packets to explain experimental data from the photoelectric effect. This model contributed to the development of quantum mechanics. In 1914, Robert Millikan's experiment supported Einstein's model of the photoelectric effect. Einstein was awarded the Nobel Prize in 1921 for "his discovery of the law of the photoelectric effect",[4] and Millikan was awarded the Nobel Prize in 1923 for "his work on the elementary charge of electricity and on the photoelectric effect".[5]
Color photography The foundation of virtually all practical color processes, the three-color method was first suggested in an 1855 paper by Scottish physicist James Clerk Maxwell, with the first color photograph produced by Thomas Sutton for a Maxwell lecture in 1861.[3][4] Color photography has been the dominant form of photography since the 1970s, with monochrome photography mostly relegated to niche markets such as art photography.