Let’s play a game and think about a question that asks you to answer five green things. What do you think of first? Green plants everywhere, like the green plants on my desk, green and oily. Magnetic nail, green water, green, white board, green recycling bin, green paner, fluorescence lid, exit lights, there are traffic lights 🚥, fat green parrot, George dinosaur, camouflage, the dollar, the national flag, a pool table, you can’t see the look of green grassland, there are a group of living in Mr., Wolffy a??? 🐸🐢🍏🥝 Green travel, low carbon environmental protection. Leave a comment and let me know your answer.

(Image from the Internet) The Klevan train tunnel in Ukraine

Green

What we’re going to talk about today is green in the RGB color model.

16 color names and hexadecimal mappings defined in CSS Level 1

Recently, WHEN I was studying RGB color model, I found a very interesting thing. In the CSS Color Keywords, the RGB value of red is #FF0000, blue is #0000FF, and green is #008000. Shouldn’t it be #00FF00? Lime, green and yellow, where’s yellow? Am I blind?

Opacity \ color red green blue
100%
red – FF0000 \colorbox{#FF0000}{red – FF0000}
lime – 00FF00 \colorbox{#00FF00}{lime – 00FF00}
b l u e – 0000 F F \color{#0000FF} blue-0000FF
50%
maroon – 800000 \colorbox{#800000}{maroon – 800000}
green – 008000 \colorbox{#008000}{green – 008000}
n a v y – 000080 \color{#000080} navy – 000080

CSS Level 1 accepts only 16 basic colors, called VGA colors, because they are derived from the set of colors displayed by VGA graphics cards and are called VGA Colors. Initially, browsers accepted other colors, and since some early browsers were X11 applications, these colors were mostly x11-named color lists, although there were a few differences. SVG 1.0 was the first standard to formally define these keywords; CSS Color standard 3 also formally defines these keywords. They are often referred to as expanded color keywords, X11 colors, or SVG colors.

The specification states that the earliest naming comes from the VGA palette for Windows, but why? Logic? You didn’t think about the future, right?

Mysterious mail

Find an email on the subject that says something like this.

Chris asked why the color names in SVG 1.0 are different from those in X11, and which one is correct? The most conflicting is the naming of green, because it is the primary color in the RGB model.

April 23, 2002 7:29:28 p.m. \color{green} April 23, 2002 7:29:28 p.m. April 23, 2002 7:29:28 p.m. April 23, 2002 7:29:28 p.m. April 23, 2002 7:29:28 p.m. April 23, 2002 7:29:28 p.m.

The naming of Green has a long history, starting with HTML3.2, then HTML4, CSS1, CSS2, and finally XSL, SVG. Green is defined as a half-strength green primary colour, half the strength of a completely opaque green lime, like Maroon and Red. This standard has been around for years, and you can find it in Netscape 1, MSIE 2 and Opera 1. The earliest can be traced back to 1931 international color standards for objective measurement. It is better to establish standards, trust W3C, blah blah blah, and mention that there is no actual conflict, just a set of naming rules for colors.Copy the code

The international standard for color in 1931 :CIE 1931 Color Space

Three primary colors were obtained using standard wavelengths, 700 nm (Red), 546.1 nm (green) and 435.8 nm (blue).

the human eye can actually see light with wavelengths up to about 810 nm, but with a sensitivity that is many thousand times lower than for green light. These color matching functions define what is known as the “1931 CIE standard observer”.

I looked at the measurement process, but I didn’t understand it very well, and I didn’t find the specific reason for the name, except that scientific experiments show that human eyes perceive green light more strongly than red and blue light.

conclusion

In Web development, green means #008000, not #00FF00, which is called Lime. The term comes from the early HTML and CSS specifications. In HTML and CSS, the English name green can be used instead of a hexadecimal value. In the earlier X11 color specification, green/ Lime had the same hexadecimal value, both #00FF00.

In the final

Pulled so much, also do not know to say did not say clearly, and just began to say the students cuckold, don’t walk after school. And what kind of sheep is a happy Goat anyway? Why is qingqing Grassland called Qingqing grassland?

The resources

  1. Office Green
  2. CIE 1931 Color Space
  3. Color Value
  4. X11 Color Set
  5. Green and 00FF00
  6. Awesome Color
  7. Color Tool