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Adobe Photoshop CS3

Special Terms

Photoshop is a program that allows you to work with graphics and photographs. To understand Photoshop completely, you must first become familiar with special terms used in the program. This document provides definitions of many terms you may encounter when working with Photoshop.

Return to topImage Modes

Image mode refers to Bitmap, Grayscale, Duotone, Indexed Color, RGB Color (red, green, blue), CMYK Color (cyan, magenta, yellow, black), Lab Color, and Multichannel. Image modes display colors in slightly different ways and each has special characteristics for certain applications or uses. Below you will find descriptions of the image modes in order of appearance in the Image » Mode menu.

Displays images in black, white, and 254 shades of gray. This mode will allow you to use layers and certain filters. Working in this mode also allows you to save the file in several file formats, including jpeg and gif formats.

This image mode is only available after the grayscale image mode has been selected. The duotone image mode has four types of tones: mono, duo, tri, and quad. Thus, you can select either one, two, three, or four tones to represent your image. Duotone is like grayscale, except you select the tones that will be used to create/represent your picture, and these may be any color.
Duotone Image mode

Indexed Color
This image mode is constrained to a color palette of 256 colors or less. In this mode you cannot add layers, apply filters, or add colors that are not already used in the image. You cannot use most of the editing tools. This mode allows the file to be saved as a gif, psd or pdf (Photoshop formats), or png. Saving as other types of files may cause a distorted image.

RGB (recommended)
This image mode has three channels: Red, Green, and Blue. RGB mode is the recommended working mode for images in Photoshop. It allows you to apply layers, filters, and non-constrained color palettes. Working in this mode also allows you to save the file in several file formats, including jpeg and gif formats.
RGB pallete

This image mode has four channels: cyan, magenta, yellow, and key (black). These are the colors that printers use when printing a document. Since monitors use RGB, the colors may not appear to be the same color when they are printed; therefore, you should use CMYK image mode when you want the colors in your document to print exactly how they are used in the document.

Lab Color
This image mode has 3 channels: lightness, chroma A and chroma B. Chroma A controls 128 colors ranging from green to red. Chroma B controls 128 colors ranging from blue to yellow. Lightness controls the luminosity of the image. Some filters are disabled in this mode: artistic, brush strokes, sketch, and texture.
Layers pallete, channel tab

This image mode has 3 channels: Alpha 1, Alpha 2, and Alpha 3. This mode has 256 colors: black, white, and 254 colors of gray. This mode is for specialized printing.

Return to topAdditional Terms

Aliased vs. Anti-Aliased options
Photoshop allows you to create anti-aliased text. Anti-aliased edges on a selection or text produces a smooth-edged appearance. This effect is produced by automatic blending of the edge pixels with the surrounding pixels. If aliasing is turned on (aliased), a jagged, stair-stepped appearance results.

Squares (pixels) of color placed in uniform rows to form an image. You can save as a Bitmap file (bmp or btmp) and several other file types.

Canvas size
The height and width dimensions of the the area in which your image is created. You can add white space behind your image, which will appear as a border of blank canvas around the image.

Color bands
Distinct bands of color visible on an image after the reduction of the color palette of an image.

Dots per inch/pixels per inch. These are resolution measurements used by scanners, printers, and Photoshop. The resolution of computer monitors is 72 dpi/ppi. Gif and jpg images should be adjusted to this resolution for final saving and display.

Fills an area with color or a percentage of color (opacity). See also Paint Bucket.

Special effects that are applied to all areas, selected areas, or layers of the image. You can choose from a variety of effects, from adding artistic rendering to sharpening and blurring images.

Uses the tolerance specified in the Magic Wand Options palette to select pixels adjacent to the selected pixel.

Image size
The overall size of an image in print size. Print size can be determined by percent, inches, centimeters, points, or picas. Using Image size, you can choose measurement type and adjust height and width dimensions and resolution.
NOTE: Use caution when increasing the resolution or actual dimension of the image: it may reduce the sharpness of your image.

Layers act as separate films, much like transparency sheets. Each layer contains objects which, when viewed together, create a composite image.

The transparency that you affix to a tool, layer, or color. The lower the percentage is, the more transparent the effect; the higher the percentage, the more opaque the effect.

Paint Bucket
Applies color to an area within the tolerance setting of the pixel addressed. This differs from Fill because it affects those pixels within the tolerance, whereas Fill affects all pixels within the selection.

A grid square that consists of one color. In combination with all of the other pixels, it makes up the image that we see on screen. All Photoshop images are bitmapped into pixels.

Selects like-color pixels throughout the image.

A border applied using the foreground color to selected portions of an image. Stroke is measured in pixels and can be placed on the outside, center, or inside of the selection.

A value range from 0-255. The lower the value, the more similar the color that will be selected. The higher the value, the broader the color range that will be selected.

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