Final answer:
The central idea of "Dorothea Lange: Portrait Photographer" is Dorothea Lange's significant role in documenting the Great Depression through photography, particularly with her iconic image 'Migrant Mother'.
Step-by-step explanation:
The central idea of "Dorothea Lange: Portrait Photographer" revolves around Dorothea Lange's contributions to documentary photography during the Great Depression. Lange, with her ability to sit motionless due to her polio-affected leg, captured powerful images that represented the struggles of that era. Her iconic photograph, Migrant Mother, showcased the resilience of a generation of Americans facing the hardships of the Dust Bowl and economic downturn. This photo and others like it illustrated the human impact of the Great Depression, prompting government action and the establishment of aid programs such as unemployment insurance.
Lange's early life experiences and health challenges significantly shaped her photographic work and allowed her to create images that communicated the emotional depth and adversity faced by many during the 1930s. Migrant Mother and other photographs by Lange were not only artistically impactful but also carried strong social and historical significance, influenced by Lange's personal perspective and the technical aspects of early photography like the Daguerreotype.