Buzzwords

LAN: Local Area Network.

LANDSCAPE (MODE): An image orientation that places a photograph across the wider (horizontal) side of the monitor or print. Photographers call this a horizontal image, while computer users prefer to use the term landscape. Antonym: portrait or vertical. While most computer screens are horizontal, a few use a mercury switch that senses the orientation as the user physically rotates the screen from portrait to landscape.

LAPTOP (COMPUTER): A portable computer designed to (surprise) fit on a users lapas opposed to a desktop model. Laptops typically have a flat screen and weigh less than 10 pounds, although the trend is toward bigger screens and lighter weight. These days, most laptops sport ports that let you connect an external monitor (or an LCD projector for presentations) and full-size keyboard allowing them to be used as desktop models.

LASER: Light Amplification from the Stimulated Emission of Radiation. A device that uses precious stones, such as rubies and emeralds, to produce a precisely focused light wave that is used in communications, printing, and disk storage. While some people think of lasers as relatively new technology, they were originally developed in 1957.

LASERJET: A family of laser printers from Hewlett-Packard. Introduced in 1984, the first LaserJet made the desktop publishing revolution possible and changed, forever, how people print all kinds of paper documents from letters to books. LaserJets printed only in black and white, but in 1994 HP introduced the 24-bit Color LaserJet, which was capable of printing 16.7 million colors at 300dpi.

LASER PRINTER: A printer that uses the same kind of process used by copiers to print. Inside the printer, a laser paints dots of light onto a light-sensitive drum and powdered toner is applied to the drum and then transferred onto the paper. IBM introduced the first laser printer in 1975, but it wasnt until Hewlett-Packard introduced their LaserJet, this, for the first time, made desktop publishing practical.

LASERWRITER: A family of 300dpi laser printers originally introduced by Apple Computer in 1985. All models in the family handled bitmapped fonts and some offered PostScript capability.

LATENT IMAGE: (1) In traditional photography, this is the image thats created when a photograph is first capturedwhen the shutter is snappedbut the film has not yet been processed. When a roll of film is finished but not processed, its full of latent images. (2) In the computer world, the definition is similar when applied to electronic and digital image making. A latent image is an invisible image created by electrical charges. For example, in a laser printer, a latent image of the page to be output is created on the drumbefore that image is transferred to the printed page that emerges from the printer.

LAUNCH: The act of causing a program to be loaded into RAM and started. This is usually accomplished by double-clicking a program (or file) icon with your computers mouse.

LAYER: Images in Adobe Photoshop and other image-editing programs are composed of many parts including layers. The base of a Photoshop document is its background, which you might think of as the photographic paper used in a conventional wet darkroom. Layers are like additional emulsions added to the surface of that paper that allow you to create new and additional effects without interfering with whats on the other coatings. One of the easiest ways to understand Layers is to imagine a photograph with sheets of clear acetate stacked on top one another. Any imagetext, graphics, or even another photographcan be placed in its own, separate layer. In the space where there is no image, you can see through to the layers below.

LCD: Liquid Crystal Display. A technology that uses rod-shaped crystal molecules that flow like liquid. This is the type of display found in laptop computers, but is found increasingly on desktop computers as well. In a dormant state, the crystals direct light through two polarizing filters, showing a neutral background color. When power is applied, the crystals redirect light that is absorbed in one of the polarizers, causing a dark appearanceor numbers, characters, and part of a photographto be formed.

There are two basic types of LCD displays: active and passive matrix. Passive displays appear in less-expensive laptops and provide reasonably sharp images for monochrome screens but are much less impressive in color. One of the other negatives of passive matrix is that the cursor or pointer will occasionally disappear in a visual effect called submarining. Most computer users find this annoying, so these kinds of screens are rarely seen anymore. Active displays are often used for color screens, but some monochrome screens, like the one in my old Apple PowerBook 180 laptop, used an active matrix display. For color applications, transistors are built into each pixel on the screen. A typical VGA (Video Graphics Array) screen requires 921,600 transistorsone for each red, green and blue dot.

LCD PRINTER: A printer that uses a single light source directed by liquid crystal shutters instead of a laser to produce laser-like quality output and speed.

LED: Light-Emitting Diode. LEDs use less power than normal incandescent light sources, but require more power than LCDs and are often used as light sources in film scanners.

LINE SCREEN: This is a method used by printer to reproduce continuous tone photographs. The technique, also known as line frequency, is created by shooting the original photograph with a graphics art camera through a halftone screen that has many tiny dots in it. These dots are lined up in diagonal rows and the number and size of dots vary depending on the type of reproduction desired. You will often hear printers toss around numbers like 80 and 133 line screen. Heres what they mean: The lower numbers inversely relate to the size of the dots. The dots on a 133 screen are smaller but more numerous than on an 80 screen. Newspapers, because of the paper stock they use, often use a coarser line screen. Thats why if you look closely at photographs in newspapers, you can see the dots.

LOAD: This procedure occurs when a computer accepts a program or any form of data (including Photo CD and other forms of graphic image files) from an external storage devicefloppy disk, Zip disk, CD-ROM, etc.and stores it in the computers RAM.

LOCAL BUS: A communications path on a computers motherboard that is located between the CPU (Central Processing Unit), RAM (Random Access Memory), and expansion cards for peripheral devices that run at the speed of the CPU and is measured in MegaHertz (MHz.)

LOSSY COMPRESSION: This is exactly what it sounds like: Compression techniques that reduce the amount of information in the data (photograph) rather than just the total number of bits used to represent that information, The theory is that the lost information being removed is less important to the overall image quality of the file and can later be recovered during decompression by interpolation. Some images can afford small losses of resolution in order to increase compression and reduce file size, but that depends both on the original image and the application you have for that image. The Joint Photographic Expert Group (JPEG) file format uses a lossy compression technique, while GIF (Graphic Interchange Format) does not.

LUMEN: A unit of measurement used for light. A 100-watt light bulb, for example, typically generates 1200 lumens.

LUMINANCE: The amount of brightness, measured in lumens that is given off by a pixel or area on a computer monitor. It is the black/gray/white information in a video signal. The color model used by Kodak for its Photo CD process involves the translation of data originally in RGB form into what scientists would call luminance and chrominance and the rest of us call color and hue.