HTML RGB and RGBA Colors
An RGB color value represents RED, GREEN, and BLUE light
sources.
An RGBA color value is an extension of RGB with an
Alpha channel (opacity).
RGB Color Values
In HTML, a color can be specified as an RGB value, using this formula:
rgb(red, green, blue)
Each parameter (red, green, and
blue) defines the intensity of the color with a value between 0 and 255.
This means that there are 256 x 256 x 256 = 16777216 possible colors!
For example, rgb(255, 0, 0) is displayed as red,
because red is set to its highest value (255), and the other two (green and blue) are
set to 0.
Another example, rgb(0, 255, 0) is displayed as green,
because green is set to its highest value (255), and the other two (red and blue) are
set to 0.
To display black, set all color parameters to 0, like this: rgb(0, 0, 0).
To display white, set all color parameters to 255, like
this: rgb(255, 255, 255).
Experiment by mixing the RGB values below:
RED
255
GREEN
0
BLUE
0
Example
rgb(255, 0, 0)
rgb(0, 0, 255)
rgb(60, 179, 113)
rgb(238, 130, 238)
rgb(255, 165, 0)
rgb(106, 90, 205)
Try it Yourself »
Shades of Gray
Shades of gray are often defined using equal values for all three parameters:
Example
rgb(60, 60, 60)
rgb(100, 100, 100)
rgb(140, 140, 140)
rgb(180, 180, 180)
rgb(200, 200, 200)
rgb(240, 240, 240)
Try it Yourself »
RGBA Color Values
RGBA color values are an extension of RGB color values with an Alpha channel
- which specifies the opacity for a color.
An RGBA color value is
specified with:
rgba(red, green, blue,
alpha)
The alpha parameter is a number
between 0.0 (fully transparent) and 1.0 (not transparent at all):
Experiment by mixing the RGBA values below:
RED
255
GREEN
0
BLUE
0
ALPHA
0
Example
rgba(255, 99, 71, 0)
rgba(255, 99, 71, 0.2)
rgba(255, 99, 71, 0.4)
rgba(255, 99, 71, 0.6)
rgba(255, 99, 71, 0.8)
rgba(255, 99, 71, 1)
Try it Yourself »
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Reference: https://www.w3schools.com/html/html_colors_rgb.asp