What does photogram mean?
A photogram is a photograph-like image created by exposing light-sensitive material directly, usually with the object resting on it, rather than by passing light through a camera lens. In modern surveying and mapping, the term also refers to a photograph or digital image used as the basis for measurements of the size, shape, and position of objects. The distinction is one of function as much as technique: a photogram in photogrammetry is an image treated as measurable evidence, while a photogram made as a print is an artistic or experimental form of photography. The word is specialized and is not normally used as a general synonym for photograph. Its unusual spelling reflects a family of Greek-derived terms built around photo- (“light”) and -gram (“writing” or “record”). A photogram therefore records the effects of light, whether through direct contact with sensitized material or through the geometric analysis of a captured image.
A photograph or digital image used as the basis for geometric measurements, especially in photogrammetry.
"The researchers extracted precise measurements from the aerial photogram."
This is the principal technical sense in surveying, mapping, and photogrammetric analysis.
An image made by exposing light-sensitive material directly, usually with an object placed on the material and without the use of a camera.
"The exhibition included photograms made from flowers and leaves exposed on photographic paper."
This sense is associated with experimental photography and photogrammetry as an artistic process.
The regular plural is used for both measurable images in photogrammetry and images produced by direct light exposure.
"The collection contains several photograms of plants made on sensitized paper."
A photogram can create a photograph-like image without a camera: place an object on sensitized paper, expose it to light, and let the object leave its shadow.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does photogram come from?
Photogram combines the Greek-derived combining form photo-, from phōtos (“light”), with -gram, from gramma (“writing,” “letter,” or “record”). These elements reflect an image made through light that can function as a photographic record. Its relatives photograph, photography, and photographic share the same photo- element, while -gram also appears in words such as telegram.
How photogram is actually used
Technical and relatively uncommon. It is especially associated with photogrammetry, aerial surveying, and experimental or alternative photography.
Easily confused with photogram
A photograph is ordinarily captured with a camera, whereas a photogram is either an image made by direct exposure to light or, in photogrammetry, an image treated as a basis for measurement.