Adobe 65045315 Photoshop Elements Manual - Page 334

USING PHOTOSHOP ELEMENTS 10 328 Glossary image cache A section of hard disk space used as virtual memory. The image cache speeds the on-screen redraw of high-resolution images. image mode The color mode of an image, such as Grayscale or RGB. indexed color A color that is rendered by using a pixel value as an index to a panel of 256 or fewer colors for interpretation. interlaced video Video generated by a system developed for early television and still in use in standard television displays. Video is displayed on-screen at 30 frames per second (NTSC) or 25 frames per second (PAL). Each frame is divided into two interlaced fields, each displayed for 1/60 of a second. The odd field contains all the odd-numbered scan lines, and the even field contains all the even-numbered scan lines of a video frame. The human eye perceives the information in two sequential interlaced fields as one unified frame. (See also "progressive scan" on page 331.) interlacing The display of a series of low-resolution versions of an image in a browser while the full image file is downloaded. J jitter Specifies the randomness of a brush stroke. JPEG Joint Photographic Experts Group. A committee of experts that develops algorithms for compressing computer image files. Also, any graphic file to which a JPEG algorithm is applied. JPEG is the format generally used to share photographs over the web. JPEG compression A lossy compression technique that reduces image data and file size. (See also "lossy compression" on page 328.) K kumimoji See "tate-chuu-yoko" on page 333. L layer A mechanism for overlaying and combining multiple images. Layers are like transparent sheets of acetate (clear plastic) that you can stack and rearrange. In addition to ordinary image layers, there are special kinds of layers. (See "fill layer" on page 326 and "adjustment layer" on page 321.) layer group A collection of layers saved with a Photoshop image. When you open a file with a layer group in Photoshop Elements, individual layers in the set are hidden in a read-only folder. To edit a layer group in Photoshop Elements, you must first simplify the layer. layer mask A protected area in an adjustment layer. Areas below the mask cannot be edited. Levels Functionality for adjusting color and tone. With a Levels adjustment, you can set shadow and highlight values to use a full tonal range, adjust middle tones only, correct color casts, and so on. locked A file that is set as Read Only. In the Photo Browser, locked files display with a lock icon. locked layer A layer in the Layers panel that has the lock icon applied. No changes can be made to a locked layer. A Background layer is always locked. lossless compression An image-compression technique that prevents image degradation caused by data loss. Lossless techniques usually use lower compression ratios than lossy techniques. lossy compression An image-compression technique using compression ratios that result in the loss of some image data. Last updated 1/2/2012