Acronym for input / output. Input may be a camera, tape, disk, video, scanner, and output may be tape, disk, CD-ROM, film recorder, printer.
The International Colour Consortium, An industry group that has endorsed a standard format for device profile.
This is a little picture on a computer screen that represents the various functions of the computer. Generally the user clicks on an icon to start an application or function.
Formerly Cibachrome. A type of colour printing that produces positive prints directly from transparencies.
Is the term quantifying the illumination of, or incident light falling on a surface.
The use of a device, such as a scanner or digital camera, to create a digital representation of an image. This digital representation can then be stored and manipulated on a computer.
Software programs that have been designed specifically for capturing, creating, editing, and manipulating images. Examples of these programs are Adobe Photoshop, Adobe Illustrator, Macromedia FreeHand, and CorelDRAW.
Image file size
The amount of computer storage space a file requires; usually measured in kilobytes (K) or megabytes (M, MB, mgs or "megs"). An image file that is 5 x 7 inches, 8-bit gray (as in a black and white photo), resolution 300dpi, is 3M in size. (A floppy disk holds 1.3M).
Refers to the specification under which an image has been saved to disk or in which it resides in the computer memory. There are many commonly used digital image formats in use. Some of the most used are TIFF, BMP, GIF, and JPEG. The image format specification dictates what image information is present and how it is organized in memory. Many formats support various sub-formats or flavors.
Is the plane commonly at right angles to the optical axis at which a sharp image of the subject is formed. The nearer the subject is to the camera, the greater the lens image plane distance.
The general term "image processing" refers to a computer discipline wherein digital images are the main data object. This type of processing can be broken down into several sub-categories, including: compression, image enhancement, image filtering, image distortion, image display and colouring.
The amount of data stored in a image file, measured in pixels per inch (dpi).
The type of device used in digital camera and camcorders to capture an image. The 2 most common types are known as CCD (charge-coupled device) and CMOS (complementary metal oxide semiconductor)
Describes the actual physical dimensions of an image, not the size it appears on a given display device.
Hardware (scanner, workstation, printer) and software support for image as a system-recognized information type. Typically, although not necessarily, support for optical storage devices is included.
Two-dimensional reproduction of a subject formed by a lens. When formed on a surface, i.e. a ground-glass screen, it is a real image; if in space, i.e. when the screen is removed, it is an aerial image. The image seen through a telescope optical viewfinder, etc. cannot be focused on a surface without the aid of another optical system and is a virtual image.
A device that uses laser light to expose film at high dpi resolution, usually 1200 dpi or higher. Most imagesetters have a maximum dpi of 4000. When generating screens or dots for halftones, each dot is created from the smaller dots that are determined by the dpi resolution. Imagesetters come in many different sizes and formats. They can image one page at a time or they can be manufactured large enough to make imposed film for presses.
To access a separate file while working on a document within an application for use in that current document.
An electrical lamp in which the filament radiates visible light when heated in a vacuum by an electrical current.
The light actually falling on a subject, which may not be the same as the amount of light being reflected by the subject. Light falling on a surface as opposed to the light reflected by it.
A hand-held Exposure meter that measures the intensity of light falling on the subject. To use it, you usually aim the hemispheric dome toward the camera. Most incident meter can also be used in a mode to measure reflected light.
Index of refraction
A property of a medium that measures the degree that light bends when passing between it and a vacuum.
Indexed colour image
An image where each pixel value is used as an index to a palette for interpretation before it can be displayed. Such image must, therefore, contain a palette which has been initialized specifically for a given image. The pixel values are usually 8-bit and the palette 24-bit (8-red, 8-green, and 8-blue).
Film formulated to give correct colour rendition when photographing subjects under 3200K light. It is also called "tungsten" film. Most film is balance for daylight and if you use daylight film with household lamps or photographic lamps, the colours will be slightly reddish or orange. The light from an electronic flash is similar in colour rendition to daylight.
There are three black and white infrared films on the market today. Kodak's High Speed Infrared Film (HIE) has the highest IR sensitivity of the three films but sacrifices Grain size as the grain is very large. Konica Infrared film has a lesser sensitivity to IR wavelengths but has much finer grain than Kodak's. The last B&W IR film is Ilford SFX which is an ASA 200 film. The film is marketed as an extended red film, not a true IR film. The film is sensitive to only a slightly extended IR range. When shooting IR films a red filter such as a #25 is placed on the lens to cut down on the blue wavelengths that IR film is also sensitive to. Infrared films provide different results than conventional black an white films mainly in the representation of foliage. Any plant that has chlorophyll will fluoresce in the IR when in direct sunlight. The intensity of the IR light reflected bye the plants is actually quite high so the leaves of a plant appear white or very near white while the sky appears very dark because the filter does not allow the blue wavelengths to reach the film. Human skin also appears to be much whiter on IR than normal film.
In photographic terms is a distance great enough to be unaffected by finite vibration. In practice this relates to most subjects beyond 1000 meters or in landscape terms, the horizon. When the infinity distance is within the depth of field all objects at that distance or farther will be sharp. Infinite distance. In practice, a distance so great that any object at that distance will be reproduced sharply if the lens is set at its infinity position, i.e. one focal length from the film.
The region of the electromagnetic spectrum adjacent to the visible spectrum, just beyond red with longer wavelengths.
A non impact printing technology where ink droplets are propelled at the paper to form characters or graphics. Can be B&W or colour.
Any type of information that is fed into a computer. Input can come from digital cameras, scanners, keyboards or a number of other devices.
A phenomenon in a scanner in which two colours that appear the same to an observer are registered as different by the scanner, or two colours that look different to an observer are accepted as identical by the scanner. Instrument metamerism is a non-recoverable error, because the input cannot be determined from the output.
Integration in photographic analysis is defined as the method of averaging all density ( illumination ) values either in R, G, and B, or as neutral density and saving this aggregate value to determine exposure in the camera or the darkroom.
Scanner with additional image processing capabilities, such as OCR, bar code reading, etc.
Chemical treatment for adding density to an underexposed or underdeveloped negative or print. With prints, it is normally easier to re-make the print; with a negative, the loss of quality is normally so bad with all but the largest formats that the results are unacceptable.
The relative brightness of a portion of the image or illumination source.
Lens designed to be readily attached to and detached from a camera.
The process of making components or peripherals work together.
A scanning process in which all odd lines then even lines are alternately scanned. Adjacent lines belong to different fields.
A negative created directly from a colour-reversal (positive) or black-white positive film. It is the negative copy of the camera original.
1. to insert between or among others
2. to change by putting in new material
3. to estimate a missing value by taking an average of known values at neighboring points.
Interpolation is an estimation of a value within two known values in a sequence of values. A method used in software to augment the resolution of an image map. The software adds pixels to an image based on the value of surrounding pixels, thereby increasing its resolution. This method can cause artifacting. NEVER simply resize a bitmap in the drawing or page-layout program that it has been imported into. It is far better insurance to quickly resize in a painting program or rescan.
A positive transparency image generated as an intermediate step to enlarge an image in positive form either from a negative or positive material.
Interspersed Aspect Ratio
A basic requirement of certified photofinishers and certified photofinishing equipment; specifies the three system print formats - C, H and P - that users select during picture-taking must be available at photofinishing.
Inverse square law
A law of physics that states that light from a point source fall off inversely to the square of the distance. As a example, if a light is 10 feet from your subject and you move it to 20 feet, you'll only have 1/4 the lighting intensity. If you move the light to 40 feet, it will now have only 1/16th the intensity.
Inverted telephoto lens
Lens constructed so that the back focus (distance from rear of lens to film) is greater than the focal length of the lens. This construction allows room for mirror movement when short focus lenses are fitted to SLR cameras.
Creating a negative of an image
Strictly, iris diaphragm. Device consisting of thin overlapping metal leaves pivoting outwards to form a circular opening of variable size to control light transmission through a lens.
a 16-bit bus for PCs.
The international standard for representing film sensitivity. The emulsion speed (sensitivity) of the film as determined by the standards of the International Standards Organization. In these standards, both arithmetic (ASA) and logarithmic (DIN) speed values are expressed in a single ISO term. For example, a film with a speed of ISO 100/21° would have a speed of ASA 100 or 21 DIN. The higher the number, the greater the sensitivity, and vice versa. A film speed of ISO 200 is twice as sensitive as ISO 100, and half that of ISO 400 film.
Although the letters actually stand for International Standards Organization, they also indicate a film's sensitivity to light, or as more commonly referred to, its speed. The term pronounced by the individual letters: I--S--O, not as if it were the word "ayso" The early term was ASA, which stood for American Standards Organization" Slow film have an ISO rating of 100 and less, while fast films are 400 and higher.
A file system format standard developed for CD-ROMs using the CD-XA encoding standard. It is supported by Microsoft operating systems, UNIX, and Macintosh.
A colour calibration chart used in many systems to create profiles. Different IT8 targets are used to characterize different devices such as scanners and printers.
IX Information Exchange
The ability of Advanced Photo System film to communicate with devices, and devices to communicate with film; can be accomplished optically or magnetically using a thin magnetic layer on the film that records digital data.