A macrograph or photomacrograph is an image taken at a scale that is visible to the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnification, magnifying, Optical telescope#Light-gathering power, light-collecting optical instrument, such as a telescope or microsc ...

, as opposed to a

micrograph A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken ...

ic image, taken with a

microscope A microscope () is a laboratory equipment, laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic ...

. It is sometimes defined more precisely as an image at a scale of less than ten times

magnification Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a size ratio called optical magnification. When this number is less than one, it refers to a reduction in size, so ...

Materials science

This term is often applied to a three-dimensional image taken of a material using a low-power stereomicroscope. These images are used in

materials science Materials science is an interdisciplinary field of researching and discovering materials. Materials engineering is an engineering field of finding uses for materials in other fields and industries. The intellectual origins of materials sci ...

, particularly in the study of stress fractures in metals. This method can also be used to assay the fine structure of steel, in a standardized test called the Baumann method that creates a sulfur print showing the amount and distribution of sulfur inclusions through the metal structure.Arthur J. McEvily (2001
Metal Failures: Mechanisms, Analysis, Prevention
Wiley-IEEE p 90

References

Laboratory techniques Materials science {{photo-stub