Ladd-Franklin's book synthesizing decades of her color vision research was published.
In April 1929, Christine Ladd-Franklin published "Colour and Colour Theories," a comprehensive book that collected and synthesized more than three decades of her research and theoretical work on color vision. Published when she was 81 years old, the book represented the culmination of a scientific project she had pursued since her original 1892 paper.
The work presented her evolutionary theory of color vision in its most developed form, engaging critically with rival theories, particularly those of Helmholtz and Hering, while incorporating decades of subsequent experimental findings on color blindness, retinal physiology, and comparative animal vision. It served both as a scientific treatise and as a defense of her lifelong theoretical position within the broader field of vision science.
The publication was significant not only for its scientific content but as a testament to Ladd-Franklin's remarkable persistence: despite never holding a full professorship or the institutional resources typically afforded to male scientists of her stature, she continued to research, write, and publish original scientific work into her ninth decade of life.
"Colour and Colour Theories" remains an important historical document in the history of vision science, reflecting the sophistication of pre-modern color theory debates and standing as the definitive statement of Ladd-Franklin's influential evolutionary theory of color perception, a theory that continued to be discussed by vision scientists for years after her death.