T-U

thumbnail

A small graphic that represents a larger image. Thumbnails are often used in palettes to give a visual history of the states in the image.

tonality

The grayscale values from 0 to 255 that differentiate an image's pixels. Tonality is black and white and shades of gray, and it is one of the most expressive elements in an image. If you want to create a strong feeling in an image, consider exaggerating the tonality in some way.

tool preset

A user-defined set of tool parameters accessible through the Tool Presets palette. Options bar information, foreground color, and external palette information (where applicable) can be saved as part of a tool preset.

tracking

The spacing between letters in a block of text.

transform

To modify the position, scale, or proportions of a layer. Transforming a layer is useful for changing the size or placement of a layer, as well as for adding perspective or distortion.

transparency checkerboard grid

The checkerboard background that appears "through" an image when you have made some part of an image transparent. You can control the size and color of the checkerboard grid using the Preferences dialog boxes.

tritone

A grayscale image printed with three colors of ink, usually black and two additional colors for a total of three colors (called plates in the printing process).