L

Lab color

Lab is a color system that was developed as a method of calculating all the colours that are viewable by the human eye. Lab color is a mathematical model defined in terms of luminosity and brightness, as well as two axes - green to magenta and blue to yellows.

The Lab color model incorporates all the colors in the CMYK spectrum and the RGB color spectrum and is often used as an intermediary when converting one format to the other in an image editor, such as Adobe Photoshop.

LZW compression

LZW is a compression format that is used to compress certain types of bitmap graphics images (such as TIFFs). Unlike JPEG compression, LZW is a lossless compression format - I.E. file size is reduced without the loss of image quality. The downside of compressing image with LZW is that they take longer to print.

Line screen (LPI)

Also referred to as the line screen frequency, this refers to the measure of distance between the rows of dots that make up a halftone screen. Lower line screens are used on rougher, low quality printing substrates (such as newsprint), whilst higher line screens are used for high quality print jobs on smooth art papers.

See also: difference between dots, pixels and line screens.