HP manual PCL 5 Color Concepts, Color Specifications and Color Spaces

The PCL language also allows users to use patterns in combination with colors. These patterns and colors can be combined with text, vector graphics, and images to create new, complex graphics objects. The PCL Print Model determines the logical operations (known as ROPs, Raster Operations) used to combine each part of the graphic object.

PCL 5 Color Concepts

This section describes some of the concepts and terminology of color science related to the PCL 5 color commands.

Color

Color is a combination of human physiological and psychological responses to a relatively narrow band of frequencies in the electromagnetic spectrum. The frequencies visible to the human eye are called the visible spectrum. It’s useful to understand that color comes both from direct light and indirect light that has reflected from a surface. Reflected light absorbs all but the reflected frequency. The colors seen on a color monitor are combinations of different-colored lights traveling directly to the eye. They are called additive colors since the different colors combine to form the resulting color. The colors seen on a printed material such as paper are reflected from the paper surface, which absorbs some of the light. Colors seen under these conditions depend on the viewing conditions, the amount and color of ambient light, as well as the amount and color of the reflected light.

Color Specifications and Color Spaces

A given color can be described as particular amounts of three light frequencies (red, green, and blue light). For example, equal amounts of red, green, and blue light are perceived as white light. The absence of all three primary light colors is black.

EN Color Printing Overview 1-3