How did photography change by the turn of the century in America?

like how the camera changed , how the way they used it , how colored pictures came about in that time, how different films were invented and used in that thine............... i have to do it for a project and iv'e been researching it but i could barely find anything and when i do find it it's mostly about Russia .. if you could send a link .. or explain it that will be great!!!!