I'm going to post some quick thumbnail review of books which I think that we as photographers can read and study the images in them to reach a better understand of what is a photograph and how over time the photographic image has been approached. They will also look at where the photographic art fits in the broader context of the graphic arts and their history and schools. These are all books which your local library can get for you via Inter Library Loan if they do not have them. We will start with this one.
The Photographer's Eye, by John Szarkowski, Museum of Modern Art, 1966.
In
The Photographer's Eye, Szarkowski out lines five principles of the photograph which from a critical perspective can be used to differentiate it from other graphic arts. They are not independent categories but interdependent facets of the photograph. These five principles are:
The Thing Itself
The Detail
The Frame
Time
Vantage Point
Each of these principles are then illustrated by photographs take from over a 125 years of photographs to show how each principle is embodied in a photograph.
This book will help you think about just what is going on in your picture at a deeper and more critical level than just the surface and the technology.
Take a look at this book, you may find yourself looking at your work and the work of others with different eye and vocabulary for discussing your images.