Time of exposure in photography -- Brita Ness

In photography, the amount of light that reaches a film is referred to as exposure. The longer the exposure time, the more light is let in and the lighter the photo appears. When a photograph is underexposed, it is difficult or impossible to detect subtle changes in darker areas (shadows), while with an overexposed photograph it is difficult to detect subtle changes in lighter areas (highlights). In other words, in underexposed photos, dark areas appear uniformly black and in overexposed photos, white areas appear uniformly white. In pinhole cameras, larger holes and shorter focal lengths (the distance from the hole to the photographic film) let in more light and increase exposure, while smaller holes and longer focal lengths let in less light and decrease exposure.

Here is a photo that I took! It is of my chemistry lab notebook last semester -- I had a few mishaps.. The photo was taken with my android phone and then imported into photoshop and converted from color to greyscale.