Saturation (Intensity)
We usually say that a color is very vivid or intense, which means that it is a very saturated color. Saturation is what defines the intensity or degree of purity of each color. Its values vary from its maximum (any pure color) to its minimum (a gray color).
Luminosity “Value” (Brightness)
Refers to the amount of light emitted or reflected by an object, and in the case of a color we refer to its lightness or darkness. A color at 100% saturation will obtain its maximum purity at 100% lightness, and at a lightness of 0% saturation it will correspond to a specific shade of gray that will become absolute white at a value of 100% lightness, and absolute black at a lightness value of 0%.
Hue (color)
When we commonly refer to “color”, we are certainly referring to hue. In a technical sense, hue is the dominant wavelength of the color we can see, or properly speaking it is the color in its purest state, the rainbow being the best visual example. To represent the different tones we use the chromatic circle where each of them is defined by the degrees of the inclination of the radius it represents.
Contrast
In the “Theory of Color” the term contrast indicates the difference between different colors, determining the difference between darker and darker shades. To balance an image, both light and dark contrasts are used, and to know how to expertly adjust contrasts it is essential to know the complementary colors found in the chromatic circle. In this way, two tones directly opposite each other will create the maximum level of contrast.
Nuance
It is the quality by which we differentiate colors. It is an attribute associated with the dominant wavelength in the mixture of light waves, where we find the color in its purest state without the addition of white or black. Hue is the sum of wavelengths that a surface can reflect, thus allowing us to differentiate between blue and red. Hue refers to the path that a tone takes to one side or the other of the chromatic circle, so that yellowish green and bluish green will be different shades of green. Another example would be to mix red and yellow in different proportions of one and the other, thus obtaining different shades of orange and even achieving a color with a yellow hue.