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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.

Export -
To transfer an image to another format.

Filter -
An image transform tool used to process an image; for example, to sharpen, blur, or diffuse it.  Often this is a plug-in in an image editor, but filters are also built into scanning software or hardware.

FlashPix - A new image format that stores images in a series of different resolutions.

Flat - A low contrast image.

Frequency - The number of lines per inch in a halftone screen.

Gamma -
A way of representing the contrast of an image, shown as the slope of a curve showing tones from white to black.

Gamma Correction or Gamma Compensation - The process of preconditioning or adjusting an image to correct for the gamma of the device used to reproduce the image, such as a printer or display screen.  Without gamma compensation, the image will look too dark when printed or displayed.

Gang Scan - The process of scanning more than one picture at a time, used when images are of the same density and color balance range.

Graphics Interchange Format (GIF) - A compressed image format popular on the Web.  GIF was the first commonly used image format, but was largely replaced by JPEG.

Gray Component Removal - A process in which potions of an image that have all three process colors have an equivalent amount of gray replaced by black to produce purer, more vivid colors.

Grayscale - Gray values in an image.

Halftoning -
A method of representing the gray tones of an image by varying the size of the dots used to show the image.

Highlight - The brightest values in an image.

Histogram - A bar like graph that shows the distribution of gray tones in an image.

Hue, Saturation, Brightness (HSB) Color Model - A model that defines all possible colors by specifying a particular hue and then adding or subtracting percentages of black and white.

Hue - A pure color.

Interpolation -
A method of changing the size, resolution, or colors in an image by calculating the pixels used to represent the new image from the old ones.  It is also being used to increase bit-depth claims on scanners (as in "Enhanced Bit Depth" or "Enhanced Color").

Interrupt - A signal to the microprocessor to stop what it is doing and do something else. 

Invert - To reverse an image's tones to its opposite value: to make a negative.

Joint Photographic Experts Group (JPEG) -
The JPEG format offers a compression scheme that makes the image file smaller than files in other formats by discarding some of the image information.

- The orientation of a page in which the longest dimension is horizontal.

Legal size - Paper or other media that is 8 1/2 inches wide and 14 inches long.

Line Art - Images typically consisting only of black and white lines.

Line Screen - The resolution or frequency of a halftone screen, expressed in lines per inch.

Lines Per Inch (LPI) - The yardstick used to measure halftone resolution.

Luminance - The brightness or intensity of an image.  Determined by the amount of gray in a hue, luminance reflects the lightness or darkness of a color.

Mask -
To cover part of an image so it will not be affected by other operations.

Midtones - Those portions of an image with a value between black and white, usually in the 25 percent to 75 percent range.

Moire- In scanning, an objectionable pattern caused by interference of halftone screens, often produced when rescanning a halftone and the sampling frequency of the scanner (spi) interferes with the halftone or dither pattern of the original.

Monochrome - Having a single color.  Typically refers to a black and white image, but could be any single color image.

Noise -
Random information that distorts an image, especially the background distortion of an analog image before it is converted to digital format.

Optical Character Recognition (OCR) -
The process of converting printed characters into the ASCII characters and other attributes of a bitmapped image of text.

Optical Resolution - The resolution of a scanner that is calculated by dividing the width of the scanned area by the number of pixels in the CCD.  Optical resolution is also often called true resolution and does not include any interpolation to increase pixels.

Palette -
A set of tones or colors available to produce an image.

Parallel - To move data several bits at a time, rather than one at a time.  Many scanners use parallel connections to move image information, SCSI or printer parallel.

Peripheral - Hardware that extends the capabilities of the computer, such as a printer, modem, or scanner.

Pixel - A picture element of an image that refers to a single dot with in a digital photograph.  A photograph is made up of thousands of pixels.

Pixels Per Inch (ppi) - The number of pixels captured per inch by a scanner.  This is a more accurate rate term than dpi (dots per inch) when applied to scanners because scanners capture pixels.

Portable Network Graphics (PNG) - A lossless file format created to overcome deficiencies of the Graphics Interchange Format (GIF), such as the limited number of colors.

Port - A channel of the computer used for input or output with a peripheral.  A scanner interface board includes a special port that the scanner can use to communicate with the computer.

Portrait - The orientation of a page in which the longest dimension is vertical.

Posterization - A banding effect produced by reducing the number of gray tones in an image.

Preview Scan - A preliminary scan that can be used to define the exact area for the final scan.  A low- resolution image of the full page or scanning area as shown, and a frame of some type is used to specify the area to be included in the final scan.

Quantization -
Another name for posterization.

Raster Image -
An image defined by rows and columns of pixels.  Scanners capture images as raster images, although some can convert them to vector images.

Raster to Vector Conversion - The process of examining a raster image for lines and strokes, and creating a new image that looks the same but is made up of lines rather than pixels.  When a person draws, they are creating a vector image.  Vector images can be enlarged much more accurately and often have a smaller file size.

Reflection Copy - Original artwork that is viewed and scanned by light reflected from its surface, rather than transmitted through it.

Rescale - To resize an image.

Resolution - The number of pixels or dots per inch in an image.  Also the capability of a scanner to resolve detail, which requires quality optics as well as high ppi or spi.

Retouch - To remove flaws or to create a new effect in an image.

Sample Rate or Samples Per Inch -
The number of pixels per inch captured by a scanner.

Saturation - An attribute of a color that describes the degree to which a pure color is diluted with white or gray.  A color with low color saturation appears washed out.  A highly saturated color is pure and vivid.

Scalable Black-And-White Image (spi) - These images are vector drawings instead of raster drawings and can be enlarged and reduced after the scan without introducing scaling defects.  Some HP scanners can create scalable black-and-white images. 

Scanner - A device that captures images or text and converts it to a bitmapped image.

Selection Area - The part of a HP Deskscan preview scan that you select to be saved to a file or sent directly to a printer.

Small Computer Systems Interface (SCSI) - A computer industry interface standard used for connecting peripherals to personal computers.

Serial - Transmitting information one bit at a time in sequential order.  Used with modems as well as some scanners.  USB and Firewire are very fast serial interfaces.

Shade - A color with black added

Sharpening - Increasing the apparent sharpness of an image by increasing the contrast between the adjacent tones or colors.

Smoothing - To blur the boundaries between tones of an image, usually to reduce a rough or jagged appearance.

Threshold -
A predefined level used by scanners to determine whether a pixel will be represented as black or white.

Thumbnail - A miniature copy of a page or image, which gives you an idea of what the original looks like without having to open the original file or view the full size image.

Tagged Image File Format (TIFF) - A graphic file format originally developed specifically for scanners.  It can be used to store grayscale and color images and now is graphic standard image file format supported by most applications, printers, and scanners.

Transparency Adapter - An add-on device used with a scanner to scan slides and other see-through media.

TWAIN - A software driver interface between a scanner and other image capturing devices that lets you scan images from a scanning application directly into an application like Adobe Photoshop.

Unsharp Masking -
A technique used by scanners and image editors to increase the sharpness of an image.

Universal Serial Bus (USB) - An advanced serial interface that supports large numbers of devices.  USB is much faster than traditional serial interfaces.

Vector Image -
An image defined by the beginning and ending points of each line.

- To enlarge a portion of an image.

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