What does Color Value mean?
In color theory, a color value is actually a shade of lightness. IT professionals or others might use the terms “lightness” and “color value” interchangeably. Color values are often presented in a chart or graph to help developers or others to choose from various specific shades of color for the purposes of applying to visual projects.
A color value scale starts with light and ends with dark. Other categories in between might include light/medium, medium and medium/dark. Again, color values for digital projects are commonly represented on a digital graph, scale or palate for users to choose from. In addition to color values, users can add differing amounts of red, green or blue, or other primary colors to create secondary color hues.
Color values are important in providing precise choices in the vast color scale that became possible with the hardware of the 1990s. Prior to that time, digital color was mostly confined to a few individual primary colors. The rapid advancement of color display technology has led to much more emphasis on applying specific color values to displays.
The value of the color is represented by the international used color space such as LAB, LCH, RGB, XYZ, YXY,etc. LAB is the most commonly used.
CIE1976 L*a*b* color space is mainly used for paint, building material ,coating and other other surface color industries. It is also called CIELAB. L * is the brightness coordinate, which characterizes the brightness of the color. a * b * is the color coordinates, which characterizes the color tone and saturation. Please refer to figure.
L represents brightness. 0-100 represents from black to white.
a represents red to green. Positive values indicate red and negative values for green.
b represents yellow to green. Positive values indicate yellow and negative values for blue.
For example, if the products’ color value is L:22.75,A:22.58,B:13.83.
Its represents white is 22.75. Red is 22.58, and yellow 13.83.
During the measurement, the first measurement is for target, the second measurement is for getting delta E value which is also called color difference value. The difference is the value of the measured product minus the sample
value, the brightness difference △ L, red and green difference △ A and yellow and blue difference △ B.
△ L = L sample-L standard (brightness difference)
△ a = a sample-a standard (red / green difference)
△ b = b sample-b standard (yellow / blue difference)
△ L + too much white, △ L- too much black
△ a + too much red, △ a- too much green
△ b + too much yellow, △ b- too much blue
△ L *, △ a *, △ B * is the difference of brightness L * and chromaticity value a * and b * between the target and sample.
△ E represents color difference value, the calculation method and the brightness difference △ L, red and green difference △ A, yellow and blue difference △ B have a relationship.
Customers are mainly based on the △ E, brightness difference △ L, red and green difference △ A and yellow and blue difference △ B for color matching and adjusting.
△ L is positive, indicates that the measured product is brighter than the sample, negative indicates the measured product is darker than the sample;
△ A is a positive value, indicates the measured product is much more red than the sample, negative value indicates that the measured product is much more green than the sample;
△ B is a positive value, indicates the measured product is much more yellow than the sample, negative value indicates that the measured product is much more blue than the sample;
LCH color space, L is brightness, c is Chroma, H is Hue. Brightness, chroma and hue are the three basic properties of color.