In computer graphics, a color look-up table, or CLUT, is the set of available colors for a given application.
For example, a 24-bit system can display 16 million unique colors, but a given program would use only 256 of them at a time if the display is in 256-color mode. The CLUT in this case would consist of the 16 million colors, but the program’s palette would contain only the 256-color subset. To avoid dithering (i.e., varying the pattern of dots in an image) on 8-bit machines, you should only use colors from a predesignated CLUT.
A font is the overall design for a set of characters. It describes the size, weight, and spacing of a character and shouldn’t be confused with a typeface, which is a more general term.
Courier is a typeface; Courier 24-point bold is a font. Computers display fonts in either a bitmap or a vector format. In a bitmapped font, each character is represented by an arrangement of dots. In a vector font system, the shape or outline of each character is defined geometrically. Since a vector font is scalable according to the defined outline, a vector system can make many differently sized fonts from one defined set of characters. Currently, the most widely used vector font systems are PostScript and TrueType.
CMYK stands for cyan magenta yellow and blacK and is a color system used in the offset printing of full-color documents.
Offset uses cyan, magenta, yellow, and black inks and is often referred to as “four-color” printing. Monitors use red, green, and blue light instead, so they display images using a different color system called RGB. One of the great problems of the digital age has been matching colors between these two systems; i.e., taking a digital RGB image and making it look the same in print using CMYK. These problems are addressed by applications such as the Pantone Matching System.
GIMP stands for GNU Image Manipulation Program, and is a free software program for image authoring and composition, and photo retouching. The program has a scripting interface and can be expanded with plug-ins and extensions.
To crop means to cut the pieces of an image that you don’t need.
Cropping differs from resizing because when you crop an image you retain the dimensions of the image. Resizing an image actually shrinks the image into smaller dimensions.