| A | B |
|---|
| binary | mehod for working with numbers base on only two digits: 1 and 0, each of which means either "on" or "off" |
| bitmap | image composed of tiny individual dots called pixels |
| dithering | mixing different sizes and colors of pixels on the screen that trick your eye into thinking you see a new color |
| gamma | measure of contrast that affects the mid-level grays(midtones); can be adjusted without significantly affecting the shadow and highlights in an image |
| halftone | pattern used as the screen when printing a grayscale image |
| lossy compression | JPEG compression software that selects details that are important to image and discards the rest |
| pixel | hundreds of thousands of spots of light the compose a computer monitor |
| pixelation | condition where each pixel in an image becomes visible because of low resolution |
| posterization | photographic effect in which the number of gray levels in an image is reduced to achieve a poster-like effect |
| raster image | image that has been scanned, taken with digital camera, or created in Adobe Photoshop; made of pixels |
| resolution | density of dots or pixels on a page or monitor usually measured in dpi |
| scanner | digitizing device that converts art or photos into an electronic bitmap form |
| screen | pattern of dots used to make a halftone or tine, measured in percentages |
| stochastic screening | screened images that have very small dots of the same or varying sizes and varying distances between dots |
| vector graphic | image made up of independent lines, shapes, or objects that are each defined by mathmatical formulas |
| virtual memory | free space on a computer's hard disk to be used when adequate RAM is not available to work with large images or files |
| handheld scanner | used by holding scanner in your hand and dragging it across an iamge |
| sheetfed scanner | uses a roller mechanism to pull a sheet of paper over a stationary optical device and reads the image for use on the computer |
| flatbed scanner | used to scan paper images and small objects such as keys pencils, fabric swatches, etc. |
| slide scanner | specially made for scanning 35mm slides |
| drum scanner | image is wrapped around a transparent cylinder which rotates as it scans - most expensive scanner |
| scanner software | standalone program packaged with scanner used to control the scanner |
| image-editing software | software used to edit or change photographic images |
| OCR software | software that can scan text into a computer as actual letters and sentences |
| DPI | measurement of the resolution at which an output device displays text and graphics |
| PPI | measurement of input resolution |
| LPI | measurement of the screen frequency or resolution of a halftone image |
| brightness/contrast | command that offers the least amount of control over tonal range of an image |
| color balance | command that changes the mixture of colors in a color image, provides generalized color correction |
| curves | command that provids the most sophisticated controls of the tonal adjustment tools |
| equalize | command that redistributes the brightness values of the pixels in an image so they more evently represnet the entire range of brightness |
| histogram | graph in Photoshop that shows how the pixels' values are distributed in an image |
| hue/saturation | command used to adjust and enhanc the hue, saturation, and brightntess of individual color components in an image |
| invert | command that makes a positive black and white image negative |
| levels | command used to control the tonal balance of an iamge by setting the lightest and darkest point on an image |
| posterize | command that indicates the number of tonal levels for each channel in an image |
| threshold | command that converts grayscale or color images to high contrast black and white images |
| unsharp mask | filter used to correct blurring that occurs during photographing, scanning, or printing an image |
