Glossary of Terms
Background Illumination - light that illuminates the background. The background should be uniformly illuminated to remove any shadows or other lighting effects that would otherwise interfere with clearly discerning the facial outline on the background.
Centering - the orientation of the facial region within the frame; head should be positioned such that the approximate horizontal mid-points of the mouth and bridge of nose lie on a vertical line at the horizontal center of the photo width; and a horizontal line through the center of the subject's eyes can be located approximately 55% from the vertical bottom of the photo; and the width of the subject's head is approximately 50% of the width of the photo.
Composition - the content and organization of the image that is being captured for the photograph. In this context, the composition of the photograph must show a clear, front view and full face of the subject against a plain and neutral light color background.
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.
Facial Region Illumination - the light that is incident on the subject's face. The face should be clearly illuminated with all physical features shown and no shadows that would otherwise obscure the facial image.
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 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)
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.
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.
Head Orientation - the positioning of the subject's head, specifically positioning the face to the full frontal position, eyes level and open. For those individuals that wear glasses, proper head orientation is crucial in avoiding unwanted glare from glasses. Even so, care should be taken to meet the required facial area and face centering guidelines outlined in this brochure when positioning the subject's head to remove the potential glare.
Lighting Arrangement - the lighting arrangement for subject illumination which should consist of a minimum of 3 point balanced illumination; two (2) points of illumination should be placed at approximately 45 degrees on either side of the subject's face, the third point should be placed so as to illuminate the background uniformly.
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.
Print - refers to an exposed film picture that is printed on photographic paper, in color or black and white. In digital imaging, a print is the result of printing the digital image on photographic-quality paper stock using a digital printer. For passport/visa photographs, the resulting print should measure 2 inches x 2 inches (51 mm x 51 mm).
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.
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.
Subject Positioning - the position of the subject with respect to the camera; the subject should be placed in front of the background such that the focal distance from the camera's lens to the subject's face should be no closer than 120 cm.
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.