| Achromatic Color – The primary colors of light (red, green, and blue) used by scanners, monitors, and other computer devices. When combined, they produce white light. Anti-aliasing – A process used to remove the stair stepping effect found in diagonal lines of an image. Involves inserting dots of an in-between tone along the edges.
Array – A grouping of elements such as sensors.
Aspect Ratio – The relative proportion of the length and width of an image. For example, if you scan an original that measures 4 by 6 inches, it will have an aspect ratio of 4:6, or 2:3.
Attribute – Characteristics of a page or character, such as underlining, boldface, or font, that can be captured by an optical character recognition (OCR) program.
Automatic Document Feeder (ADF) – A device attached to a scanner that automatically feeds in one page at a time, allowing the scanning of multiple pages.
Auto Trace – A feature found in many object-oriented image editing programs, such as Adobe Illustrator, that allows you to trace a scanned image and convert it to an outline or vector format.
Batch – Actions carried out consecutively on a set of files.
Bilevel – In scanning, a binary scan that stores only the information that tells whether a given pixel should be represented in black or white.
Binary – Base-two arithmetic, which uses only 1's and 0's to represent numbers. 0001 represents 1 decimal, 0010 represents 2 decimal and so forth. Binary numbers are used indirectly to refer to color depth, as in 24-bit or 8-bit color.
Bit – The abbreviation for binary digit, either 0 or a 1. Scanners typically use multiple bits to represent information about each pixel of an image.
Bit Depth – The number of bits used to represent colors or tones.
Bitmap – An image represented as pixels in a row and column format. (Note that Adobe refers to a bitmap as a two-color image.
Bleed – An image that continues to the edge of the page, often accomplished by having the image extend past the edge and then trimming the page to the finished size.
Blend – To improve the transition between image areas by smoothing the boundaries between them.
Burn – To make a portion of an image darker.
Calibration – A way of correcting for the variation in output of a device such as a printer or monitor when compared to the original image data from the scanner.
Camera Ready – Artwork printed in hardcopy form, which can be photographed to produce negatives or plates for printing.
Carriage – The scanner component that moves down a page to capture an image.
Cast – A tinge of color in an image.
Charge-Coupled Device (CCD) – A type of solid-state sensor used in scanners that captures light reflected or transmitted by original.
Chrome – Color, combining hue and saturation.
Chromatic Color – A color with at least one hue available, with a visible level of color saturation.
Contact Image Sensor (CIS) – Used in smaller, low-cost scanners, a new type of image sensor that has limitations on resolution.
Clone – To copy pixels from one part of an image to another.
Complementary Metal Oxide Semiconductor Sensor (CMOS) – A new type of sensor used in scanners and digital cameras that is based upon a semiconductor process designed for digital electronics instead of analog electronics as in the CCD.
CMYK – The abbreviation for cyan, magenta, yellow, and black.
Color Correction – Modifying the color balance of an image, usually to produce a more accurate representation of the colors in an image. Color correction compensates for the deficiencies of process color inks, inaccuracies in a scan or color separation, or an undesired color balance in the original image.
Complementary Color – The opposite hue of a color, or the direct complement.
Compression – Squeezing a file (especially an image) into a more efficient form to reduce the amount of storage space required.
Contrast – The range between the lightest and darkest tones in an image. In a high-contrast image, the shades fall at the extremes of the range between white and black. In a low contrast image, the tones are closer together.
Crop – To trim an image or page.
Data Compression– A method of reducing the size of files, such as image files, by representing the sets of binary numbers in the file with shorter string that conveys the same information. Many image editing programs offer some sort of image compression as an optical mode when saving a file to disk.
Density – The lightness or darkness of an image or a portion of an image.
Desaturate – To remove color from an image or hue.
Device Driver – A software module that tells your operating system how to control a given piece of hardware, such as a scanner.
Diffusion – The random distribution of gray tones in an area of an image.
Digitize – To convert analog information, such as a continuous tone image, to a binary form that can be processed by a computer.
Direct Memory Access (DMA) – This term refers to the movement of data directly from memory to some other device, such as the disk drive, without first being loaded in the microprocessor.
Dithering – A way of simulating gray tones or colors by grouping dots so they can be merged into a intermediate colors or tones.
Dot – A unit used to represent the smallest element a printer can image, but sometimes used to represent the resolution of other devices, such as monitors or scanners.
Dots Per Inch (DPI) – The resolution of a printed page, expressed in the number of printer dots in an inch, abbreviated dpi. Scanner resolution is also expressed, somewhat in accurately in dpi.
Downsampling – To reduce the amount of information in an image, usually to make it smaller or to discard some colors when changing bit depth. Also used when reducing the number of pixels in an image.
Dropout Color – A color invisible to a scanner during grayscale scan.
Dynamic Range – The range of densities between the highlights and shadows of an image.
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