To Maris, If one were to make a photogram of a twig, laying flat on the paper, that might satisfy your definition of a photograph as factual evidence, easily read for what it is. Of course the photogram would leave out all sorts of information about the color and and values of the twig. And a photogram on paper sensitized with cyanotype chemistry would produce colors totally untrue to the twig or the light hitting it. Then if one were to place that same twig on its end, the resulting image would very likely not be read as a twig at all. A photograph is a rendering, even when done in the most documentary fashion, there is always some departure from truth. There are always decisions made by the photographer that are analogous to mark making.