Frame
When you take a picture, you frame a tiny piece of reality inside your viewfinder or smartphone screen. Excluding everything that is outside the area that the lens captures. When you look at a photograph,, you can only see what is inside the frame, of course. The first thing you see is what is placed in the middle. An easy frame is looked at like when we read a paragraph like a text, from the top left to the bottom right. All action happens within the frame, and does not trigger the viewer to the imagine a larger reality. The edges of the frame do not contain critical information about the subject or the action, and are often darker than the centre of the frame, as this keeps the viewer’s eye locked inside the photograph. Frame is simply the edges of a photograph that form and defines what we see both within, and imagine what is outside the picture.
Sources: 30 Second Photography
Sources: 30 Second Photography
Example from the internet
Own examples of frame below: