Lesson 9 - Sustainable Web Design In 20 Lessons
The entire 9th chapter of the book Sustainable Web Design In 20 Lessons.
Colors, light mode and dark mode
In this lesson, we will talk about light and dark modes. Dark mode has grown in popularity since 2017 and is commonly found on devices such as phones, laptops, websites, and TVs. But why have we started to implement dark mode on almost every device, and what benefits does it bring? Can we use dark mode to make our devices consume less energy, and is it less likely to cause eye strain? These are some of the questions we will be looking at in this lesson, and at the end, you will know exactly how different types of screens work, why some colors consume more energy, and why dark mode can help your visitors save energy.
What is LCD?
LC displays (Liquid crystal) were invented in the 1960s, but it was first in the 1970s that they could operate at room temperature. Before that, LCDs only functioned at 80 degrees Celcius, making it hard to use them in reality. It was also around this time that the dream of a flatscreen TV hanging on the wall was invented. Unfortunately, it took many years before they could use the LCD for TVs. The first pocket calculator used an LCD with a yellow filter on top, giving it a tint. It was also hard to read the content of the display because of the poor backlighting in certain conditions. It was, therefore, best to use the device in a well-lit room or in daylight. We have been using LCD for phones since 1992 when IBM invented its very first smartphone. When I write smartphone, it is not supposed to be understood as the smartphone we know today. It was a different time, so the word “smart” had an entirely different meaning. Even today, we use LCD for devices such as TV, computers, and phones, but it is more commonly seen in cheaper devices.
Liquid crystal displays are flat panels that require light and polarizers to function. They need an external backlight since the screen doesn’t produce any light on its own. You are probably familiar with how it looks when a backlight is broken on an LCD TV. Parts of the screen will become so dark that it becomes almost impossible to see what is happening. LCD consists of a backlight, a polarizing filter screen, a glass substrate with horizontal lines, twisted nematic liquid crystal, a glass substrate that determines the shapes on the screen, and a polarizing filter with a vertical axis. If you remove the glass substrate that defines the shapes on the screen, you will see a blank display with a light coming from the back.
As LCD technology developed, we started seeing colored panels, which were even more fascinating. The screen is only a light valve that decides how much light it should let through. Essentially, it can go from 0% to 100% depending on the amount of light used. To make a colored display, it is required to use an additional RGB filter which was printed directly into the LCD cell. Each pixel would be divided into three parts. One is red, the next is green, and the last is blue. The combined three colors created a square known as a pixel. By combining different amounts of red, green, and blue, it was possible to show colors.
