# Computing All the Colors of the Rainbow

The world of colors is a tremendously interesting and diverse area, and accordingly, queries on colors have been some of the most popular and recurring queries in Wolfram|Alpha since its launch. In accordance with the popularity of the domain, we have recently performed a major upgrade to the existing color functionality in Wolfram|Alpha.

Let’s start with something basic: green. In addition to the color’s alternative notations, Wolfram|Alpha provides the nearest representations in various color spaces, including HSV, HSL, HSI, XYZ, xyY, Lab, and Luv:

The x, y value for the color is shown on the CIE 1931 chromaticity diagram that follows. Alternatively, specific colors can be queried directly by specifying a color value in corresponding spaces such as #DFFF00, RGB 0.58, 0.77, 0.45, HSV 96 degrees, 42%, 77%, XYZ 70 40 50, and Lab 80 30 20.

Another group of interesting properties is the various types of nearby and related colors:

Different types of related colors can be queried individually too. For example, complement red, or simply – cyan, finds the complementary color:

Besides computing various properties of individual colors, Wolfram|Alpha allows users to do arithmetic computation with multiple colors, that is, mixing colors. Green + orange by default gives the result of additive color mixing:

The alternative results using subtractive color mixing and color blending are compared at the bottom:

The color arithmetic queries can have coefficients: 2 red + 0.5 light orange + 0.3 brown. Queries with negative coefficients by default assume subtractive color mixing: green – 0.3 chartreuse.

In addition to answering questions about particular colors, we can investigate the properties of all reds or the set of all greens.

While the span of various colors can be hard to define, in a CIE chromaticity diagram, we can generally agree on certain categories according to the colors of the visible spectrum. If we take these colors to the central white point of the diagram, we can consider the cones thus defined as the set of a particular color.

Wolfram|Alpha can show us where a color exists on the x, y chromaticity diagram and how much space it occupies out of the total volume in various different color spaces. We can also see visually how it fills a given color space.

We might also be interested in specific named colors such the set of red HTML colors. We will be adding more grouping of colors like this in the coming months.

Looking further into the colors of the spectrum, Wolfram|Alpha is able to tell us about specific colors of light such as yellow light.

This reveals a wealth of information about the physical properties of colored light that we can delve into further: What is the effective temperature of yellow light? What is the bandwidth of blue light? What is the momentum of a red photon? We can also look into questions like the color of 500 nm light.

The sun is our largest producer of visible light, and we can ask Wolfram|Alpha how much solar radiation is green. We can also look into other emitters of visible light: spectral lines of violet, red lasers, and which organisms give off cyan light.

Absorption properties of light are equally important. Plants absorb various wavelengths of light at different rates, which can affect their growth under different light sources. Asking about the chlorophyll absorption of green light will show us the relative absorption. We might cross-reference that with emission by looking for green light sources, which shows the amount of light produced for various common light sources within a given spectral range.

One of the more important absorbers of visible light is our eyes. The chromaticity diagram shows us the range of human vision while the color-matching curves that are also provided highlight the human eye’s response to differing components of XYZ color space.

We hope all this new functionality is going to be exciting for the Wolfram|Alpha community, and as always, we look forward to hearing more from our users on additional functionality they would like to see in this thoroughly “colorful” world of colors.

It is exciting!

Posted by Bo May 22, 2012 at 5:32 am

Fine work. Peripheral information about various popular color systems such as Pantone (or even the names of the Crayola Crayons past and present) would be a welcomed addition.

Posted by Vermillion Popp May 23, 2012 at 12:37 pm