rgb

There are three ways of previewing the colour

The 'Preview' panel.

The 'Additive' panel.

The 'LCD' panel. You can change the 'fuzz' slider to make it more natural.

Use the red, green and blue sliders to fine tune your colour.

You can also type or spin the numbers in the text boxes.

Enable the alpha channel (transparency) if you need it. Transparency is denoted by a checkerboard pattern. Again, you can type or use the spinner to control the value.

The RGB(A) code will display in the box. Click the copy button to copy the string to the clipboard.

The corresponding HEX (hexadecimal) code will display in the box. Click the copy button to copy the string to the clipboard.

The colour name drop down can be used to select one of the 140 standard web colours so you can see the colour and the RGB values. Note that colour names do not support the alpha channel so this will not work if alpha is enabled. If you manage to correctly guess a particular named colours RGB code, it will display in the preview and in the drop down box. Again, you can copy the colour name using the clipboard icon.