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Background

In Photoshop, the area behind layers. The contents of all layers float on top of the Background. Unlike a layer, the Background is opaque and cannot support transparency. If the document contains more than one layer, the Background is always at the bottom of the stack and cannot be moved or placed in a higher position. When new layers are added to the document, their content always appears in front of the Background.

baseline

An imaginary line on which the bottom of most textual characters are placed. Some characters , such as g and y , have descenders that extend below the baseline.

baseline shift

The movement of the baseline of a character horizontally or vertically from its default starting position. Unlike leading, which affects all of the characters in a paragraph, baseline shift affects individual characters.

Batch Action

An Action that will be applied to all of the images in a folder automatically, also known as batch processing. You can batch-process a group of images within a folder or from a different source, such as a digital camera or scanner with a document feeder.

Bezier curves

Lines and shapes composed of mathematically defined points and segments. Bezier curves are used in vector graphics.

bit depth

Refers to the amount of information per color channel. Photoshop can read images with 16 bits of information per channel, such as a 48-bit RGB or a 64-bit CMYK color image. Even though images with higher bit depths contain more color information, they are displayed on the monitor at the bit-depth capability of the computer s video card, which is 24 bits in most cases.

Bitmap mode

A Photoshop mode that displays and converts images that are composed of pixels, each containing 1 bit of information. The pixels are either black or white. Bitmap images are used to create line art and digital halftones . Bitmap image file sizes are smaller than grayscale images, which contain 8 bits per pixel, or color images, which contain 24 bits per pixel. Bitmapped images do not support layers, alpha channels, filters, or any operations involving color.

black point

The darkest pixel in the shadow areas of an image. In Photoshop, you can set this point in the Levels and Curves dialog boxes.

blending mode

A preprogrammed color formula that determines how the pixels in an image are affected by painting or image-editing and overlay operations. In Photoshop, the Mode menu on the Options bar offers a choice of several blending modes.

brightness

The relative lightness or darkness of a color, measured from 0 to 100 percent. Brightness is also referred to as value. Colors with low brightness values are dark; colors with high brightness values are light.

burn

A technique used by photographers in the darkroom to underexpose or darken areas of an image. Photoshop s Burn tool darkens by lowering the brightness values of pixels as you move the tool over the image.