## The 16 Colors and What They Are

The 16 colors are the first named colors that were available for use in HTML, a programming language used to build websites. The first 16 named colors in HTML were: aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, and white. In 1999, HTML 4.01 officially defined this list of 16. The list was first seen in HTML 3.2. Today, HTML supports 140 standard color names which all modern browsers have available.

## How were the 16 Colors Named and Chosen?

The Windows VGA palette supported these colors so it was simply a matter of naming them. Basically, the most popular computer hardware and computer software supported these sixteen colors at this time.

In simple terms, Windows 95 was a popular operating system which coordinates information sent to the computer monitor. To accomplish this, Windows used “VGA” to send a signal. VGA in this context stands for Video Graphics Array, which is a type of circuit and graphics standard used to produce the video signal. The video signal can then be sent to the monitor and display what Windows (and the user!) wants to display.

As the most popular consumer software and hardware supported these sixteen colors, it made sense to define them in the programming language used to build websites.

## What is a Color Number?

The HTML color code is a set of three numbers (0-255) that represent the amount of red, green, and blue light in an item. The first number is the intensity of red, the second is the intensity of green, and the third is the intensity of blue. These are the colors your monitor uses to display information on the screen. Combinations of red, green, and blue light create the colors you see. A color space is the set of all possible colors in a specification.

sRGB is the color system used for the HTML color names. sRGB stands for “standard RGB”. RGB refers to the red (R), green (G), and blue (B) components which compose each color. Dubbed “A Standard Default Color Space for the Internet”, sRGB was created in 1996 by employees of Microsoft and Hewlett-Packard. sRGB is still used today. iPhones use sRGB to encode colors if an extended color space is not specified.

The sRGB color space defines 16.7 million possible colors, because there are 256 values for red, green, and blue (256*256*256 = ~16.7 million). There are 256 possible values for each color component because the value is between 0 and 255, inclusively. A computer byte is able to store 256 possible values, so it is a natural choice to use this number of values. A byte is a collection of eight 0s and 1s which a computer uses to store data and perform calculations. Therefore, it is convenient to choose a range of 256 possible values. This both matches the available hardware and provides an adequate number of colors.

## What does an HTML color code look like?

As mentioned before, an HTML code must contain the three numbers for red, green, and blue, each between 0 and 255. The HTML code is written in hexadecimal format. An example of a hexadecimal HTML code is #FF00AC, where FF is red, 00 is green, and AC is blue.

The numbers 0 and 255, and all in-between, can be written in base 10 format. This is the typical number system we use in society: the numbers we use are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. If you try to count above 9, you will need an additional digit.

## Hexadecimal Explained

Hexadecimal, the format used for HTML color codes, is in base 16 format. Instead of 10 possible digit values, there are sixteen. The sixteen “numbers” are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F. That means if you wanted to write the number 10 in base 16, you would simply write “A”. You may also notice that F represents 15 instead of the 16 base 16 may imply, because we need a value to represent 0.

With this in mind, we can find the base 10 equivalent for the example HTML code #FF00AC given above. Red, FF is the max value, 255. The right most digit is F, which is 15 in base 10, and the left most digit is also F. Since it’s second from the right, we multiply it by 16 (which comes from base 16) to find it’s total. So FF represents 255 (15*16 for the left digit plus 15 for the right digit, or **15***16 + **15** = 255).

For green, the middle two digits of #FF00AC, we have 00. This one is easy because both are zero, so the base 10 representation is also 0.

Finally, we have blue. The last two digits of #FF00AC are AC. A represents **10** and C represents **12**. To find the base 10 number, we use the same process as before: **10***16 + **12** = 172. The value for blue is 172.

With these values, your computer can combine the ratio of red, green, and blue to render the color on your monitor.

## Earlier Color Names and Spaces: X11

In the 80s, it became possible to use more than just a few colors on a computer screen. In 1988, the X11 color system standardized the naming and specification of colors.

The X11 color system is based on six base colors: red, green, blue, cyan, magenta, and yellow. You can combine base colors to create the set of colors in this system.

The first three letters of the full hexadecimal code for any color represent the amount of red (R), green (G) and blue (B) in that color respectively. The next two letters represent how much cyan (C), magenta (M) or yellow (Y) is mixed with that base.

## References

You may notice that may links on this page reference www.w3.org. The World Wide Web Consortium is an international community which defines standards for the internet. In the late 90s, this group was responsible for maintaining the HTML specification. Thus, they are a primary source for its definitions of color in this time period.

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