The value dimension of color, or the intensity of white in the color, ranges from zero percent (black) at the tip of the cone to 100 percent at the top. The saturation dimension of color, which is the extent to which it departs from a neutral color such as gray, or in simpler terms, its “colorfulness”, ranges from 0 percent (gray) at the middle to 100 at the face, or curved surface of the cone’s exterior, where the colors are fully saturated. In this color model, the primary and secondary colors are arranged around the circle that represents the top of the cone, so that the hue dimension of color (what we commonly think of as “color”, such as red, orange, or yellow) can be expressed as angles varying counterclockwise from red at zero. HSV is actually just a rearrangement of the geometry of the RGB color model in an attempt to be more intuitive and perceptually relevant than the Cartesian (cube) representation. This color model is used in color printing, and its name reflects the four common components of ink formulas used by some printers and plotters.Īnother color model that ArcGIS supports is HSV (hue, saturation, and value), which can be visualized as a cone in a cylindrical coordinate system (figure 5).

The CMYK color space, a variation on the CMY model, adds black. The primary colors of the CMY color model are cyan, magenta, and yellow, and the combination of all colors is black (from AM Tait’s Ten quick references for map makers)

In this color model, the combination of all colors is black (figure 4).įigure 4. Values for the primary colors of this color model are expressed in percentages and range from 0 to 100. The CMY color space is based on a subtractive color model which describes what kind of inks need to be mixed together so light reflected from the surface and through the inks produces the various colors.Ī CMY color space can also be visualized as a cube with its primary colors (cyan, yellow, and magenta) at three corners, and its secondary colors (red, green, and blue) along with black and white, at the other corners (figure 3). This model is used for electronic devices that emit light of different colors, such as smart phones, computers, and televisions. The primary colors of the RGB color model are red, green, and blue, and the combination of all colors is white (from AM Tait’s Ten quick references for map makers) In this color model, the combination of all colors is white (figure 2).įigure 2. RGB is an additive color model because it describes what kind of light needs to be mixed together (emitted) to create the various colors. Gray is scaled along the diagonal line between the two opposing corners between black and white. In this color model, black is defined as (0,0,0) and white as (255,255,255). The values for RGB range from 0 to 255 for each dimension, yielding 256 3 (16,777,216) possible colors. With its primary colors at three corners, the secondary colors-cyan, magenta, and yellow (CMY)-in addition to black and white, are assigned to the remaining corners. This results in a 3-D cube like the one shown in figure 1. A color model is visualized as a three-dimensional space that contains all possible combinations of the model’s primary colors.Īn RGB color space is created by mapping its primary colors-red, green, and blue (RGB)-into a 3-D Cartesian coordinate system. The first thing to understand about colors in ArcGIS symbols is that they are defined using a color model, which is a system for specifying colors numerically according to their individual components. We wrap up with a set of tips for working with color in ArcGIS. In this article, we discuss colors in ArcGIS symbols, including color models and how they are used to define colors in ArcGIS, and the differences between their color gamuts. In a previous article, we discussed fonts in ArcGIS symbols, and in an upcoming article we will tackle the issue of pictures. There are three primary building blocks of standard symbols in ArcGIS-fonts, colors, and graphic files.

By Aileen Buckley, Mapping Center Lead, and Jeremy Wright, John Cranfill, and Michael Grossman, Product Engineers

Rgb primary colors