While indexing the photograph the photographer is offered two systems of classifying the image; Representative and Conceptual.
Representative categories
This field is required. Photographers must choose from the category fields that correspond with the more literal representation of the image. For example, if a photographer wishes to submit a photograph of a light bulb, they may choose the following category:
> object; Electric material > Bulb/Lamp
Conceptual categories
This field is not required and must only be used for images which lend themselves to it. Photographers must choose from the category which corresponds with the concept evoked by your photograph. The concept is the representation of an idea abstracted and evoked by the image deposited.
For example, with a photograph of a light bulb, a photographer may choose the following category:
Concept > > spirit; Imagination