RGB Value
An RGB color value represents RED, GREEN, and BLUE light sources.
In CSS, 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 between 0 and 255.
For example, rgb(255, 0, 0) is displayed as red, because red is set to its highest value (255) and the others 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
GREEN
BLUE
Example
<div class="w3-row w3-center" style="line-height:80px;color:white;font-size:20px;font-weight:bold;font-family:Consolas, 'Courier New', Courier, monospace">
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(255, 0, 0);">rgb(255, 0, 0)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(0, 0, 255);">rgb(0, 0, 255)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(60, 179, 113);">rgb(60, 179, 113)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(238, 130, 238);">rgb(238, 130, 238)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(255, 165, 0);">rgb(255, 165, 0)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(106, 90, 205);">rgb(106, 90, 205)</div>
</div>
</div>
Shades of gray are often defined using equal values for all the 3 light sources:
Example
<div class="w3-row w3-center" style="line-height:80px;color:white;font-size:20px;font-weight:bold;font-family:Consolas, 'Courier New', Courier, monospace">
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(60, 60, 60);">rgb(60, 60, 60)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(90, 90, 90);">rgb(90, 90, 90)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(120, 120, 120);">rgb(120, 120, 120)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(180, 180, 180);">rgb(180, 180, 180)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(210, 210, 210);color:#555555">rgb(210, 210, 210)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgb(240, 240, 240);color:#555555">rgb(240, 240, 240)</div>
</div>
</div>
RGBA Value
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
GREEN
BLUE
ALPHA
Example
<div class="w3-row w3-center" style="
line-height:80px;
color:white;
font-size:20px;
font-weight:bold;
font-family:Consolas, 'Courier New', Courier, monospace;
background-image:url(img_bg_eyeicon.png), url(img_bg_transparent.gif);
background-repeat:no-repeat, repeat;
background-position:center, top left;
background-color:#ffffff;">
<div class="w3-col m6 w3-padding">
<div style="background-color:rgba(255, 99, 71, 0);color:#555555;">rgba(255, 99, 71, 0)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgba(255, 99, 71, 0.2);color:#555555;">rgba(255, 99, 71, 0.2)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgba(255, 99, 71, 0.4);">rgba(255, 99, 71, 0.4)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgba(255, 99, 71, 0.6);">rgba(255, 99, 71, 0.6)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgba(255, 99, 71, 0.8);">rgba(255, 99, 71, 0.8)</div>
</div>
<div class="w3-col m6 w3-padding">
<div style="background-color:rgba(255, 99, 71, 1);">rgba(255, 99, 71, 1)</div>
</div>
</div>