I wonder if there is a best practice or rule to handle the payment of people you photograph for documentary purpose. Especially extreme cases like, e.g. a child living on the street.
There are no absolute rules but what you do depends on the circumstances.
- In some case you may be required to compensate the subject. If you intend to use the photo for commercial purposes, you will need a model release form. Depending on local-laws, sometimes these must include an exchange of value in the contract. This can be monetary payment or something else with perceived value, such as the copy of the photo itself.
- To get a photo for editorial use, you will usually not need a model release but you may still offer payment at your discretion.
- If someone asks for payment to pose before you take a photo, I would be wary about the documentary value of the resulting photo.
- If someone asks for payment after you take a photo, it would be at your discretion. Considering the shot was candid and documented what was actually happening, paying would not diminish the documentary nature of the shot, only encourage such behavior. I would avoid it but certainly offering to send a copy would be a nice gesture.