UCA: UCA adds cyan, magenta, and yellow where black is present in a photograph or neutral colors in an image. UCA gives density to an image and increases ink coverage. UCA is not generally desirable in offset printing or screen printing and should be set to 0 percent.
UCR: A choice in the Color Settings dialog box. Choosing UCR before printing reduces the amount of C, M, and Y ink in the darkest neutral areas of the image when the colors exceed the specified ink weight configured in the Color Settings dialog box. Thus, UCR is better suited for newsprint where ink is heavily restricted.
Undo: The Undo command is usually accompanied by the name of the last tool used, such as Undo Paint Bucket or Undo Trim. Undo simply moves back one step and reverses the last action taken. The Undo command is not available after a file has been saved.
Unsharp Mask: Available from Filter>Sharpen>Unsharp Mask. Increasing the values in this dialog box makes the edges, pixels, and colors in the image sharper (they’ll stand out more) so that when you lose sharpness during the print process, the final product will look similar to the original.
Use All Layers: To apply a selected tool to all of the layers in the image, place a check in this box. For instance, when using the Magic Wand to select a specific color, you can choose to apply the selection to all of the layers in the image instead of the default of only the active layer.
Vector data: Type and shapes are vector data. Vector data is computed mathematically, and the object or type is defined by it geometric shape. Type, shapes, and vector masks are all considered vector data.
Vector masks: Created from paths, these masks can be used to mask (or hide) part of a layer, they can be edited by configuring styles or adding special effects, and they can be used to reveal specific areas of a layer. Vector masks are created with the Pen and Shape tools.
Vector type layers: These type layers are the optimal choice when possible because they are printed as vector data and are thus much cleaner, less pixelated, and a whole lot easier to screen print than rasterized type.
Vellum: A paper used in both laser and inkjet printers for outputting color separations. The vellum is then used to burn the screen used at the printing press.