Glossary
of Photographic Terms
Ambient Light - the available light completely surrounding a subject
that is not introduced artificially.
Aperture
- the opening in a camera lens through which light passes; measured
in f-stops.
Background
- the area behind the subject
Background
Illumination - light that illuminates the background.
Bit -
short for binary digit, which in a computer is the smallest unit
of storage.
Brightness
- the amount of light and dark areas in an image.
Byte -
short for binary term; a collection of computer bits; on many
modern computers, a byte is equal to eight bits.
Cast -
See Color Balance, Color Cast & Color Correction
Color
Balance - how a color film reproduces the colors of a scene; using
the wrong lighting can cause the colors to appear washed out or
unnatural.
Color
Cast - the overall bias towards one color in a color image.
Color
Correction - applying filters which help balance the color rendition
of a scene to match the color response of the eye
Composition
- the content and organization of the image that is being captured
for the photograph.
Continuous-Tone
- refers to an image where like colors in the subject and scene
do not change abruptly; the opposite of posterization.
Contrast
- the range of difference in the light to dark areas of an image.
Diffuse
Lighting - lighting that is low or moderate in contrast, such
as on an overcast day.
Dot -
the smallest element that can be printed by a digital printer.
Exposure
- in photographic terms is the product of the intensity of light
and the time the light is allowed to act on the film, or digital
camera sensor. In practical terms, the aperture controls intensity
or amount of light and shutter speed controls the time.
File Size
- the size of an image in digital photography, measured in kilobytes
(KB), megabytes (MB), or gigabytes (GB). File size is proportional
to its pixel dimensions; images with more pixels may produce more
detail at a given printed size, but they require more disk space
to store and are slower to print.
Film -
photographic emulsion coated on a flexible, transparent base that
records images or scenes.
Film Speed
- the sensitivity of a film to light, indicated by a number such
as ISO 100. The higher the number, the more sensitive or faster
the film. (ISO stands for International Organization for Standardization)
Filter
- colored piece of glass or other transparent material used over
the lens to emphasize, eliminate, or change the color of the entire
scene or certain areas within a scene.
Focal
Length - the distance between the film and the optical center
of the lens when the lens is focused on infinity. The focal length
of the lens on most adjustable cameras is marked in millimeters
on the lens mount.
Focus
- the adjustment of the distance setting on a lens to define the
subject sharply.
Focus
Range - the range within which a camera is able to focus on the
selected subject; i.e., from 4 feet to infinity.
Foreground
- the area between the camera and the principal subject.
Graininess
- the sand-like or granular appearance of an image. Graininess
becomes more pronounced with faster film and the degree of enlargement.
In digital imaging, graininess may occur as a result of printing
an image, the pixel resolution of which is too coarse, or as a
result of using a printer with poor dot resolution.
Grayscale
- term used to describe an image that only contains shades of
gray
Hue -
the attribute of colors that allows them to be designated as red,
green, blue, or any intermediate combination of these colors.
Lens -
one or more pieces of optical glass or similar material designed
to collect and focus rays of light to form a sharp image on the
film or digital camera sensor.
Natural
Expression - The subject's expression should be natural, with
both eyes open. Please refer to the photographs found on this
website for acceptable facial expressions.
Negative
- the developed film that contains a reversed tone image of the
original scene.
Neutral
Gray Card - a gray test card without any hue, typically of 18%
reflectance.
Neutral
White Card - a white test card without any hue, typically of 90%
reflectance.
Over-exposure
- refers to a condition where too much light reaches the film
or digital camera sensor, either because it is too bright or has
been applied too long, resulting in a very light photograph.
PPI -
short for pixels per inch; the measurement of resolution for displaying
or printing digital images.
Pixel
- short for picture element; a single picture element of a digital
photo or displayed image. Taken together, all of the millions
of pixels form a grid that represents the content of the image.
Pixelization
- the graininess in an image that results when the pixels are
too big, relative to the size of the image.
Positive
- the opposite of a negative, an image with the same tonal relationships
as those in the original scenes, for example, a finished print.
Posterization
- the effect produced when a photographic image is displayed or
printed with too few colors or shades of gray; the opposite of
continuous-tone.
Print
- refers to an exposed film picture that is printed on photographic
paper, in color or black and white.
Printing
- producing the final photo of the captured image which should
enable fine facial features to be discernable, whether the print
results from conventional photographic processes or digital printout.
The resulting print should exhibit a continuous-tone quality regardless
of the print method used.
Proper
Lighting - the type and position of lighting for both the subject
and background so that the subject is clearly illuminated with
no shadows on the face or the background.
RGB -
the way that the colors are recorded in digital imaging. A large
percentage of the visible spectrum can be represented by mixing
red, green and blue (RGB) colored light in various proportions
and intensities.
Reflectance
- the light intensity emitted from a surface in a given direction.
Resolution
- refers to a measure of the detail that can be seen in an image;
the higher the resolution, the finer the detail that can be seen.
sRGB -
refers to a standard default RGB color space. This is a device-independent
color space designed to remove any color-bias from the representation
of an image on the specified device.
Sharpness
- refers to whether an image appears to be in focus.
Subject
Pose - the subject's head, face and shoulders which should be
oriented
Subject
Positioning - the position of the subject with respect to the
camera
Tone -
refers to the degree of lightness or darkness in any given area
of a photo.
Under-exposure
- refers to a condition where too little light reaches the film
or digital camera sensor, either because the light is not sufficient
or it hasn't been applied long enough; it results in a very dark
photograph.