I3 – the signal generated by the smallest (3bit) pits on a compact disc. The Red Book specification for i3 is 0.3 to 0.7  millivolts. A means of ensuring compatibility with all types of domestic and commercial players. See Red Book.

I11 – the signal generated by the largest (11 bit) pits on a compact disc. The red book specification for i11 is = or > 0.6 millivolts. See Red Book. The relationship and position of I3 and I11 can be expressed in terms of asymmetry. This represents the ratio of pit to land length and can indicate the size of the pits on a Compact Disc. Positive asymmetry indicates the pits are longer than the lands. Red Book specifies and asymmetry of negative 20% to positive 20%.

IBL – Image Based Lighting. The simulation of light emitted from an infinitely distant (environment) sphere to create photo-realistic images. With image-based lighting, an environment texture (an image file, ideally HDRI) is needed to illuminate the scene and provide the necessary environment reflections.

IC – Integrated Circuit.

IEEE – the Institute of Electrical and Electronics Engineers.

IEEE 1394 – more commonly known as Firewire – a computer connector that permits high-speed data downloading from a digital camera. IEEE 1394 ports are typically found on high quality video and digital cameras.

IF – abbreviation for “internal focusing”.

i/o – input/output. Typically refers to sending information or data signals to and from devices.

IP (Internet Protocol) – standard networking protocol, or method, which enables data to be sent from one computer or device to another over the internet.

IQ – traditionally understood as Intelligence Quotient, a test score intended to measure human intelligence. When referring to cameras, IQ has come to mean Image Quality – a picture quality level that is not specifically defined.

IRE scale – the scale to determine video signal amplitudes devised by the Institute of Radio Engineers, an American organization now called the Institute of Electrical and Electronic Engineers (IEEE). The IRE scale includes a total of 140 units, with 100 up and 40 down from zero.

irq –  interrupt request level. In IBM-PCs, a setting given to peripheral devices like soundcards and CD-ROM drives that identifies them to the computer’s CPU. When the peripheral needs to communicate with the CPU, it will send an interrupt with that value. Problems will result if two or more peripherals are set to the same irq value.

ISO – film speed or digital photography sensitivity is designated by a single, almost universally-accepted common rating  system developed by the International Organization for Standardization which uses the initials “ISO” before the film-speed number or digital camera’s sensitivity setting number – e.g. ISO 100. (Note that many sources will tell you that the initials I.S.O.  when referring to photography stand for “International Standards Organization,” but they do not. ISO is derived from the greek word “isos”, which means equal.)

ISO 9660 – an international standard file system devised for CD-ROM discs to enable them to be read on as many computer operating systems as possible.

IVR – interactive voice response is a technology that allows a computer to interact with humans through the use of voice and DTMF tones input via keypad.

IX – a feature of the APS (Advanced Photo System) is its encoding on the film itself of picture-taking and processing data. IX (information exchange) technology allows photofinishing equipment to read instructions on the film and therefore make processing and printing adjustments to provide the best results from different lighting and exposure conditions, and also allows such features as mid-roll change.

i signal – one of the two color signals, containing reddish orange and bluish green components to which the human eye is sensitive.

IBM microdrive – a form of removable media in a digital camera that performs as a mini hard drive, in capacities up to 1 gigabyte.

icon – a symbol representing a program, file or function. See also my Image Glossary for more about icons.

iconoscope – a part of a video camera in which light is converted into electric waves.  The iconoscope [from the greek words “ikon” (image) and “skopion” (to look at)] was an early electronic camera tube used to scan an image for the transmission of television, a new approach, one that relied entirely on electronics rather than a combination of electronic and mechanical devices, such as the Nipkow Disc. Vladimir Zworykin had the idea of projecting an image onto a special plate, which was covered with tiny dots of a chemical that is sensitive to light; this broke up the image into thousands of picture elements or “pixels”. Within glass housing, the iconoscope contained a photosensitive plate or “mosaic,” which divided the image to be televised into tiny sections called pixels.  an electron gun, also placed in the housing, projected a scanning beam of electrons toward the plate. deflecting coils directed the electron beam, which charged the plate’s pixels. The charge of individual pixels was proportional to the brightness of light initially focused on them, so that the electrical signal produced derived from the original image.   After the electron beam swept past a pixel, the pixel retained an electric charge, which was then fed to the output of the camera. From the output of the camera tube, the signal traveled to an amplifier before being transmitted to a receiver.  There had been other attempts to produce an all-electronic camera tube, but the Zworykin model was easier to manufacture and produced a very clear image.

identification and location metadata –  anything that can identify a bit of essence media (ie, file source type, location of a videotape, etc.).

idle roller –  free turning non-sprocketed rollers for guiding film through its appropriate path.

illuminant –  light source used to project the film image or to expose the film.

image – 1. a term commonly substituted for “photograph” or “picture,” an image can be a two-dimensional reproduction of a scene.  2. the invisible image formed in a camera or printer by the action of light on a photographic emulsion. See also my Image Glossary for more about image.

image aspect ratio – a comparison of the width and height of an image. an example –  the aspect ratio of a 35mm frame in landscape orientation is 1 – 1.5 because the frame is 24mm tall by 36mm wide. (36 divided by 24 is 1.5, so a ratio of 24 to 36 is reported as 1 to 1.5, or 1 – 1.5, or 3 – 2.)

image-editing program – software that enables you to alter an image, usually with the objective of removing flaws, and generally improving its appearance or the appearance of the subject of the photograph.

image enhancer – video signal processor that compensates for picture detail losses and distortion occurring in recording and playback. Exaggerates transitions between light and dark areas by enhancing high frequency region of video spectrum.

image layers – images edited in image-processing applications may be made up of a number of layers, each of which contains part of the image. When the layers are combined, a single image results.

image mode – see color mode.

image orientation –  laboratory function that assures that the projected image is properly formed on the screen, and that the sound track is on the appropriate side of the film.

image-processing program – see image-editing program above.

image processing stage –  stage in the process where the digital intermediate files are manipulated and altered digitally.  Operations such as conforming, color correction, creation of special looks, and addition of special effects are all performed digitally in the image processing stage.

image sensor – 1. also called the “imaging sensor” or just the “sensor”. A digital camera’s image sensor records the scene being photographed in a similar manner to film in a traditional camera. Unlike film, the image sensor does not store the image.  It is transferred from the sensor to be stored on the digital camera’s media, leaving the sensor free to record the next image being photographed.  2.  high-end video is limited to a fixed arrangement of sensors on the charge coupled device, or CCD.  See also pickup.

image stabilization – often referred to as “IS” and also known as “vibration reduction” or “VR” – a feature in some lenses and camera bodies (and also binoculars and camcorders) that minimizes the effect of camera shake at slow shutter speeds, helping to prevent image blur. Optical IS, the preferred method, employs sensors that detect camera motion and compensate for its effects by moving lens elements or by moving the camera’s image sensor. Digital is employs software. You may see the term “anti-shake,” which is not image stabilization technology, but instead increases a camera’s ISO sensitivity to provide a faster shutter speed.

imax –  a widescreen format that originates on 65 mm film. trademark of imax corporation, the term applies more to “the imax experience” – big film, special theatres, and surround sound.

impedance – the total of the resistive and reactive opposition, measured in ohms, that a circuit presents to the flow of alternating current at a given frequency; opposition to alternating current measured in ohms; it may vary with frequency of the applied current; also referred to in microphone technology as hi z and lo z.

imposition – the drawn indication of the components of a job placed in their final position required for printing.

in-betweening – same as interpolation. in traditional animation in-betweening is a tedious process of drawing less important frames between key-frames, done by a league of betweeners. Key-frames are drawn by the animator. in computer animation in-betweening is completely handled by the computer.

in-camera editing – assembling finished program “on the fly” as you videotape simply by activating and pausing camcorder’s record function. Reduces or eliminates post-production work, but allows less control over finished program and usually imposes quality concessions. See edit.

in the can – same as “that’s a wrap” to indicate that the scene or program which has been completed.

inches per second –  refers to the length of tape traveling past a read or write head during playback or recording. Inches per second is a valid metric for all magnetic tape and machines (both audio and video), but is normally indicated only for variable speed machines such as open reel audio. Abbreviations include ips, in/s, and in/sec. Higher speeds facilitate a broader range of frequencies able to be recorded on a tape, which generally means more fidelity.

incident light – light falling on a surface, not the light reflected from it. Incident light rays are those that strike an object, that fall upon the surface of a body.

incident light meter – an exposure meter (generally hand held as opposed to a reflective meter that is built into a camera) that reads the amount of incident light. s\Since the meter does not read the light reflected from the subject, the subject’s reflectance does not affect the exposure reading. Incident light meters are equipped with one of two types of light receptor diffusion cover – a round diffuser for three-dimensional subjects and a flat one for two-dimensional, flat subjects, such as a map or painting. Also called an ‘ambient light meter’, or ‘incident meter’.   An incident light meter reads the light falling on the subject.

independent film – also indie. A movie not produced by a major studio.

index print – thumbnail-size prints on a single sheet showing all photographs taken on a roll of film. Each tiny print is individually identified for printing.

indexing – ability of some VCRs to electronically mark specific points on videotape for future access, either during the recording process (VISS –  Vhs Index Search System) or as scenes are played back (VASS –  Vhs Address Search System).

inductance – 1. the ability of a magnetic field to transfer electrical current in a conductor.  2. Inductance is a property of an electric circuit by which a changing magnetic field creates an electromotive force, or voltage, in that circuit or in a nearby circuit. Inductance is also defined as the property of an electric circuit that opposes any change in current. In 1831, Michael Faraday, an English scientist, discovered that a changing magnetic field in a circuit induced a current in a nearby circuit. Joseph Henry, an American scientist, independently made this discovery at about the same time. The generation of an electromotive force and current by a changing magnetic field is called electromagnetic induction. The operation of electric generators is based on the principal of inductance.

inductive reactance –  1. the opposition to the flow of alternating current by the inductance of a circuit, measured in ohms.  2.  Reactance, in electricity, measure of the opposition that a circuit or a part of a circuit presents to electric current insofar as the current is varying or alternating. Reactance is present in addition to resistance when conductors carry alternating current.  Inductive reactance is associated with the magnetic field that surrounds a wire or a coil carrying a current. An alternating current in such a conductor, or inductor, sets up an alternating magnetic field that in turn affects the current in, and the voltage (potential difference) across, that part of the circuit. An inductor essentially opposes changes in current, making changes in the current lag behind those in the voltage. The current builds up as the driving voltage is already decreasing, tends to continue on at maximum value when the voltage is reversing its direction, falls off to zero as the voltage is increasing to maximum in the opposite direction, and reverses itself and builds up in the same direction as the voltage even as the voltage is falling off again. Inductive reactance, a measure of this opposition to the current, is proportional to both the frequency f of the alternating current and a property of the inductor called inductance (symbolized by L and depending in turn on the inductor’s dimensions, arrangement, and surrounding medium). Inductive reactance XL equals 2π times the product of the frequency of the current and the inductance of the conductor, simply XL = 2πfL. Inductive reactance is expressed in ohms. (The unit of frequency is hertz, and that of inductance is henry.) Inductive reactance XL causes the voltage to lead the current.

infinity – distance from the camera that is far enough away that any object at or beyond it will be reproduced sharply when the lens is focused on its infinity setting. The infinity setting is usually identified by the ‘8′  (rotated 90 degrees) symbol.

infrared (IR) – 1. a frequency range of light used to send information. Remote controls and other wireless devices use IR; bluetooth uses IR.  2. nonvisible radiation from the long wavelength portion of the electromagnetic spectrum.

infrared film – photographic film that is sensitive to infrared radiation.

infrared focusing indicator – a mark on the barrel of a lens that indicates proper focusing when using infrared film. The mark is typically a red or white line that is slightly apart from the focusing indicator for normal film. Sometimes the letter “r” is next to it.

ingenue – A young actress; also, a type of role played by a young actress, generally implying a young, fresh-faced, naive character.

inharmonic –  containing frequencies that are not whole-number multiples of the fundamental. See harmonic.

initializing – Also known as formatting, initializing refers to the preparation of a digital camera’s image memory card’s contents to enable digital image data recording.

ink – 1. v., to sign a contract. 2. n., press coverage.

input (stage) –  acquisition and transfer of all analog and digital media into “the DI pipeline”.

input-looping – a device’s input loops back out so that the incoming signal can be sent elsewhere.

input selector – a routing switcher or auxiliary bus used to expand the number of video or key inputs that can feed an input of a digital picture manipulator or keyer. many keyers only accept one key source and fill, but by connecting an input selector to those inputs, many more source and fill signals become available just by selecting crosspoints on the input selector.

insert – a close-up shot of an object, often produced by the second unit.  The term probably came about to reflect the fact that this shot will be “inserted” into the final version of the movie during editing.

insert edit – 1. an electronic edit in which the existing control track is not replaced during the editing process. The new segment is inserted onto a prerecorded blank video tape.  2. placing a section of a source clip in the time line with the media currently to the right of the insert point moved farther to the right to accommodate the new clip.  3. an electronic edit where the original video and audio are replaced with new footage. Also see assembly edit.

insert shot – a close-up shot used to hide an edit or to emphasize a detail.

insertion cursor –  double triangles that appear on the FX tracks showing where the filter will be inserted.

instantaneous recording –  also referred to as acetates or lacquers. These discs could be cut and played back instantaneously, unlike other types of discs that needed processing before playback. Became common in the 1930s for both the broadcast and commercial industries and gained popularity up until the introduction of magnetic tape. A lacquer coating is affixed to the base which is usually aluminum, although you may encounter glass or cardboard bases as well.

insulation – material applied to a conductor that is used to isolate the flow of electric current between conductors and to provide protection to the conductor; also known as the dielectric.

intended ratio – also  original aspect ratio.  The aspect ratio in which a film was created and the creators intended it to be shown.

intentional over- or under-exposure – Intentional over-exposure or underexposure is known as increasing or decreasing exposure.  Many professional photographers will consistently underexpose (decrease exposure of) some slide films on purpose.

intensity modulation (IM) – used in fiber optics as a method of transmission in which the analog signal directly modulates the light source.

interchangeable lens – one of a system of detachable lenses of different characteristics, generally focal length variety, each of which fits a given camera body.

intercuttability –  can mean different things to different cinematographers.  At the very least, it encompasses how well a group of films match one another for color reproduction, color saturation, contrast, tone-scale neutrality, flesh-to-neutral, and latitude.  Chemically, there are also provisions made for how well dye sets match between films.  If two films offer significant differences from one another in any of the above categories (different contrasts for example), they may still be considered artistically compatible or complementary, but not necessarily intercuttable.

interface –  1. a linkage between two things. a user interface is the system of controls with which the user controls a device.  Two devices are said to be interfaced when their operations are linked electronically. An interface box is often required to convert signals from one form to another. For example, in order to get midi data in and out of a computer, you need some type of midi interface hardware. This may hook to an existing port on the computer, such as the printer port, or (in the case of the ibm-pc) it may consist of a circuit board that is plugged into one of the computer’s internal slots.  2.  A boundary between adjacent components, circuits or systems that enables the devices to exchange information. Links between multiple devices.

integrated circuit – an electronic device in which both active and passive circuits are contained in a single miniature multi-pin package.

interior – also ‘ int’. Used in a slug line, indicates that the scene occurs indoors.

interlace –  1, technique for increasing picture repetition rate without increasing bandwidth by dividing a frame into separate fields. 2. the manner in which a television picture is composed scanning alternate lines to produce one field, approximately every 1/60 of a second in NTSC. Two fields comprise one television frame resulting in the ntsc television frame rate of approximately 30 fps.

interlaced –  a display system in which two (2) interleaved fields are used to create one (1) frame. The number of field lines is equal to one-half of the frame lines. Interlacing fields allows the level of light on a screen to be more constant thus reducing flicker.

interlaced scanning – the scanning process that combines odd and even fields of video to produce a full frame of video signal. Interlaced scanning was introduced to the television signal in the early days of transmission standards. it was an effective way to offset the decay or loss of brightness in phosphors that were in use in cathode ray tubes (CRTs) that were in use.  Interlaced scanning allowed for a near constant brightness of the image to be maintained. Scan lines or horizontal lines of pixels (called fields when grouped together) load in an alternating fashion in an interlaced signal. Each line is scanned very quickly –  for example, most broadcast television in the United States has a frame rate of 29.97 frames per second, so each field is scanned in at
1/59.94 of a second. Adding both fields together produces one complete frame. Even though DSLRs shoot using progressive scanning at some point, it’s a good bet that your footage might be shown on an interlaced system.

interlacing – a method of using video display techniques to improve the output quality of fast animation. One video frame is divided into two fields of equal amount of scan-lines. every one line belongs to the first field, every other to the second. The image is refreshed with the nominal rate of 25 times per second (PAL), but the fields are actually shown one at a time. This doubles the refresh rate to 50, which reduces image flickering. This feature can be used effectively to diminish the strobing effect often produced by fast moving objects by rendering every frame twice, one field at a time, producing two images that are half the resolution in height. For example, at the frame 10, frames 10,0 and 10,5 are calculated and then merged together, field by field, to produce an image of normal dimensions. When viewed on the computer screen, a single interlaced image may look strange. Only when played back from video, the enhanced quality becomes apparent. The aforementioned video image refresh rate (25 PAL) should not be confused with the screen refresh rate, which on the computer today is often 72 Hz (times per second).

interlock –  a system that electronically links a projector with a sound recorder.

intermediate – Film used for making duplicate negative; film used only for making duplicates from which other duplicates or prints are made. Does not include camera films.

intermittent –  1. not continuous but equally spaced (sometimes random) motion, as the intermittent (24 fps) motion of film through a projector.            2. Stopping and starting at regular intervals.

intermediate copy –  also called reproduction master. An intermediate copy is a good quality copy of the original recording. It is produced for making lower resolution derivative files, improving access, and decreasing the use of preservation copies. See additional description and NARA’s internal specifications from the U.S. National Archives And Records Administration.

internal focusing – lens in which internal lens groups shift during focusing so that the external length of the lens does not change.

internal sync – synchronizing signals generated by a camera, recorder, or other picture source without reference to or need of external synchronizing signals.

internegative (IN) –  a negative copy made from the interpositive. the internegative, also known as, a dupe negative (DN) can be printed with one-light (one set of timing lights) since all color corrections were made in the interpositive (IP). A duplicating film stock that turns into negative when printed from a positive print, this facilitates high speed printing for theatrical releases.

interocular distance –  the distance between the centers of the lenses of two recording cameras. A typical distance would be 63.5 mm (approximating average adult eye layout). the term ‘interaxial’ is sometimes also used interchangeably with interocular’; when referring to eyesight , ‘interpupillary’ is often used.

interpolation –  1. progressive calculation of a parameter between key frames.  2. change of state of an object over time,  between two consecutive key-frames.   3.  Interpolation is a mathematical way of regenerating missing or needed information. for example, an image needs to be scaled up by a factor of two, from 100 pixels to 200 pixels. The missing pixels are generated by interpolating between the two pixels that are on either side of the pixel that needs to be generated. After all of the ‘missing’ pixels have been interpolated, 200 pixels exist where only 100 existed before, and the image is twice as big as it used to be.  4. Completing waveform data by estimating missing values. the values are estimated as being between other known values. To convert a waveform recorded at 22000 Hz or samples per second to one at a higher rate such as 44000 samples per second requires interpolation. 5. the procedure of adding new pixels to a digital image between the image’s existing pixels. Interpolation software analyzes the adjacent pixels to create the new ones when enlarging an image file. The objective is to increase the size of an image while maintaining its resolution by creating new pixels that fill in the gaps between existing pixels, all the while comparing the values of the new pixels with those of adjacent pixels. See bicubic interpolation.

interpositive (IP) –  a master positive print. The original cut negative for a feature film is printed onto intermediate stock to create a color interpositive (or master positive). The same color timing for making the answer print is used here. With the IP in hand, an internegative (IN or DN) is made which becomes the printing master or dupe negative (DN) for making multiple release prints.

interpretive metadata –  this can be language descriptions, scene/take, character, camera angle, artists/creators, organizations, etc. Imagine all dialog automatically translated (speech-to-text) and associated and linked to the spoken word.

intertitles – a title card appearing intercut with a scene. Contrast with subtitles. Commonly used with silent films.

intervalometer – a camera’s device that takes a number of consecutive exposures at set intervals for time-lapse photography.  Some cameras have built-in intervalometers; others can be fitted with an accessory intervalometer.

inverse kinematics animation – animation method that consist on positioning the ending limb of an articulated “chain” to obtain an automatic pose or articulation of the whole chain.  Inverse kinematics is based on the following principles –  1. joints are constrained with specific positional and rotational properties.  2.position and orientation of parent objects is determined by the position and orientation of child objects. Inverse kinematics is often easier to use than forward kinematics and user can quickly create complex motions; however, it sacrifices some of user’s control to the automation of the IK functions.

inverse square law – an equation that relates the intensity of a light source to the illumination it produces at a given distance. Light diminishes over distance in accordance with the inverse square law, which states that doubling the flash-to-subject distance reduces the light falling on the subject to one-quarter.  2. law of physics stating that the measurement of some physical quantity or strength is inversely proportional to the square of the distance from the source of that physical quantity. Applied to light and sound in a/v.

iris diaphragm – also sometimes simply known as “iris,” and also as just “diaphragm,” a device of thin overlapping metal leaves inside a lens, that move inwards or outwards, creating an aperture of variable size. The iris diaphragm controls the size of the aperture (the lens opening). The aperture size controls the amount of light passing through the lens to the sensor or film. See aperture.