Photographers use different techniques to create a photograph. Choosing where to stand, what kind of lighting to use, how to frame the image, and what to include -- or exclude -- from the image all effect the final product. Therefore the photograph that you see is not just a reflection of reality. It it a reflection of the photographer's point of view, and the photographer's version of reality.
Documentary photographers like Lewis Hine were doing more than capturing images. They were using images to shape public opinion on issues that, they believed, demanded social change. Hine put it this way: "Photography can light-up darkness and expose ignorance."
When you look at Hine's photographs pay attention to how the children are dressed, where the photograph was taken, and how the image is presented. Does the photograph look staged? If so, why do you think Hine's staged it that way? How do the children look? Happy, tired, poor, well-dressed? What do these details suggest to you?
Pay special attention to the words Hine used when he captioned his photographs. Remember: These captions are primary documents, too. What do they tell you about Hine's values? His biases? His vision of the working-class world?