Basics #01 How to see and see colors
Nowadays, there is an abundance of colorful and beautiful prints and images, and tools are becoming available that allow anyone to easily create and communicate using color. Color information is also easily available. However, when it comes to using colors, you may feel confused. It may be difficult to understand because it is so familiar. So, I would like to think about color again.
The difference between “seeing” a color and “how it appears”
![Diagram: Difference between “seeing” a color and “how it appears”](/ja/column/img/fig0101.png)
The ability to see color is a state that exists due to the relationship between light, the object that reflects the light, and the visual sense of the human receiver. When the light changes, the appearance changes. When the elements that make up an object differ, the visible color changes. Conditions such as surface irregularities also change the way light is reflected, which is another condition that causes the color to change. The composition of the photoreceptor cells of the recipients also varies depending on the individual, and there is diversity.
Colors appear differently depending on the light
First, let's look at the relationship between light and color. Light is a type of electromagnetic wave, and there is a range of visible light that humans can see. Colors appear when that light hits an object and is reflected or absorbed. Without light, we cannot see color, and the source of light is important.
![visible range of the human eye](/ja/column/img/fig0102.png)
![Radiant energy (relative ratio)](/ja/column/img/fig0103.png)
![Comparison of general fluorescent lamps and high color rendering fluorescent lamps](/ja/column/img/fig0104.png)
![Color chart for color rendering evaluation](/ja/column/img/fig0105.png)
However, from the perspective of products and product planning, we are not just thinking about accuracy. We often plan according to the light sources used in the final store, and we often plan according to the usage situation, focusing on how it will look in that usage situation.
In terms of the expressiveness of light, there is also a term called "color temperature." It is expressed in units such as 5,000K (Kelvin) during the day, 3,000K in the morning and evening, and 6,000 to 7,000K in the cold, lonely atmosphere in the shade. Changing the color temperature of the lighting can completely change the atmosphere.
![Differences due to color temperature of lighting](/ja/column/img/fig0106.png)
There are differences in the appearance of objects depending on their surface condition.
Next, let's look at things that receive light. Due to the nature of the photosynthetic pigment chlorophyll a, leaves of trees, which are familiar to us in our daily lives, mainly absorb red light (wavelength 650-700 nm) and blue light (wavelength 350-450 nm), while green light Since it doesn't absorb much, only this green light is reflected, making it appear green. Colors are determined by the materials each object is made of.
Also, the way light is reflected changes depending on the glossiness and matte feel of the surface. This will also change how the colors appear. White is not truly white unless it is in a state called full gloss, and the same goes for black. Matte black looks whiter than glossy black. When you think about color, you also think about the material and texture.
![Specular reflection and diffuse reflection](/ja/column/img/fig0107.png)
Humans have different ways of seeing due to differences in photoreceptor cells.
What will happen on the human side? The mechanism by which humans see the colors of objects is that the light that enters the retina through the eye is received by the rod and cone cells of the photoreceptor cells and transmitted to the optic nerve. Rod cells perceive light and darkness, and cone cells differentiate into cells that respond to red, green, and blue, and function to detect differences in color. Here too, the way we see changes when it is bright and when it is dark, and when it gets dark in the evening, it is easier to see blue colors such as light blue. This is called the Purkinje phenomenon. This phenomenon was discovered in 1825 by Mr. Purkinje of the Czech Republic. This is used for traffic signs and other purposes from the perspective of traffic safety. Also, wearing blue clothes makes you stand out, making it perfect for an evening date.
![How we see due to differences in photoreceptor cells](/ja/column/img/fig0108.png)
Know the difference in appearance and devise ways to utilize it.
As mentioned above, the appearance of colors changes depending on the conditions, so some people may find them unstable and difficult to understand. However, on the other hand, wouldn't it be better to first think about what kind of atmosphere you want to create and what kind of things you want to make look beautiful, and use lighting and colors to achieve that goal? Look closely at colors, understand how they change, and have a clear direction and policy. Then think about the method. This is the first step in color planning.
October 1, 2014
Text by Japan Color Design Institute