As my college teacher said, the definition of color:
Color is sensory experience which is generated when the light of characteristic spectrum arouse receptors in eye retina (part of the eye responsible for creating an image of the visual world). Color is ascribed to object surfaces, materials, light source(s) and its absorption, reflection or emission of light spectrum characteristics as well.
People (and other organisms) who see colors normally, majority including me, are called trichromats. Those can see the whole palette of color hues. I'll explain hue later.
Trichromacy is the possessing of three independent channels for receiving color information called cone cellls.
In short lines, light, which is electromagnetic radiation comes to the object which reflects, absorbs and does transmission (usually all three) toward human eye. Eye's retina, which is light-sensitive, trigger nerve impulses when the light comes to it. Impulses travel to the brain's vision center, where are processed so we experience colors.
Light sources can be direct or indirect. Direct light sources are divided into natural and unnatural. Indirect light sources are object which reflects, absorbs and does transmission as I mentioned earlier. Visible light is usually defined as having wavelengths in the range of 380–700 nm.
Sun light is originally white, but it is dispersed into different colors depending on refractive index - describes how light propagates through material. The range of 380-700 nm is visible to people - red wavelengths is the longest (640-700 nm) and it's the fact and reason why STOP signs and traffic lights for STOP is red. Violet is "the shortest color" (around 380-400 nm).
Unfortunately, not everyone sees the same.
Retina is made of layers of neurons, but only neurons that are directly sensitive to light are the photoreceptor cells. There are 2 types: rods and cones. Rods function is to provide black and white vision, actually, it serves the sharpness of the vision while cones functionality is color perception.
The Ishihara test is a color perception test for red-green color deficiencies. Its target is to check if a person has good color vision or is part or fully color blinded. The test contains a sample on a paper full of colored dots which form a number and those with normal color vision easily see it. It is named after its designer Dr. Shinobu Ishihara. It is a common test in driving school.
As stated on Color blind awareness official site:
People with ‘faulty’ trichromatic vision will be colour blind to some extent and are known as anomalous trichromats. In people with this condition all of their three cone types are used to perceive light colours but one type of cone perceives light slightly out of alignment, so that there are three different types of effect produced depending upon which cone type is ‘faulty’.
Laic said, That is disorder in which person has all 3 cones for colors but 1 cone perceive color a little bit different.
There are three types of anomalous trichromacy:
There are several color blindness disorders, and in all of these people are confused with some of color hues, and they can't uncover and be sure about what color it is about.
Protanopes are more likely to confuse:
Black with many shades of red
Dark brown with dark green, dark orange and dark red
Some blues with some reds, purples and dark pinks
Mid-greens with some oranges
Deuteranopes are more likely to confuse:
Mid-reds with mid-greens
Blue-greens with grey and mid-pinks
Bright greens with yellows
Pale pinks with light grey
Mid-reds with mid-brown
Light blues with lilac
The most common colour confusions for tritanopes are light blues with greys, dark purples with black, mid-greens with blues and oranges with reds.
Attributes which define colors are ton of color ( hue ), the amount of gray in color ( saturation ) and lightness of color ( brightness ).
HSB color space is in other words how our brain works.
Hue is a ton of a color as I said, that means that hue is any color our brain can differentiate, e.g. red, violet, brown etc.
Saturation is dose of gray in color so for example at value of zero saturation everything would be black, white or grayscale.
Brightness refers to how close on the scale from white to black the color is.
For example, brown color in HSB would be around 25% orange, 50% saturated and because it's dark around 30% bright.
There are 2 types of color mixing/system:
RGB is called additive synthesis because you get different colors by adding colors on white base.
Red + Green = Yellow
Red + Blue = Magenta
Green + Blue = Cyan
Each part of the color varies between 0% and 100% and all 3 colors together gives white.
RGB model is used on screens ever since LCD monitors came by.
CMYK is a subtractive color mixing template that is primarily used in printing.
Cyan + Magenta = Blue
Cyan + Yellow = Green
Magenta + Yellow = Red
All 3 colors, in theory, gives black, but in reality it's equal to dirty brown or something like that, so designers developed K which means Key ( Black ) to make it really black.
WHITE - perfection, purity, safeness, simplicity..
BLACK - sadness, evil, elegancy, mystery, night...
BLUE - peace, trust, intelligence, creativity, freedom..
BROWN - stability, friendship, house, care, productivity...
GREEN - relaxation, freshness, life, stability...
RED - passion, fire, speed, power...
YELLOW - optimism, happiness, memory, organization, energy...
PURPLE - luxury, wealth, dignity, delicacy, pride
Personally, my favorite color is green. Green color scientifically proven relaxes brain and is most widespread color besides blue.
