Gnome is notorious for reducing user options in the GUI to a minimum. So if you want to use a solid color background instead of a wallpaper, your only option using the UI is to select an image of whatever color you want your desktop background to be.
As someone who does not like any distracting elements on the desktop, this feels tedious to me.
Fortunately, the functionality is still in the code. It’s just not accessible through the UI.
Use these settings for Gnome >= 41:
gsettings set org.gnome.desktop.background picture-options none
gsettings set org.gnome.desktop.background primary-color '#008080'
gsettings set org.gnome.desktop.background color-shading-type 'solid'
and these settings for Gnome < 41:
gsettings set org.gnome.desktop.background picture-uri none
gsettings set org.gnome.desktop.background primary-color '#008080'
gsettings set org.gnome.desktop.background color-shading-type 'solid'
Replace #008080 with whatever hex-color code you like.
Andrew McCarthy has more details in his blog .
Here are two classic suggestions for background colors:
#008080: ██ (Windows NT 4 default)#3A6EA5: ██ (Windows 2000 default)
And yes, I can see the irony in suggesting Windows colors for a Linux desktop ;)
Hint: If you want to find out more about the different settings available in gsettings, you can use gsettings list-schemas to list all setting-schemas (like namespaces) and gsettings list-keys org.gnome.desktop.background to list all keys in a schema (e.g. org.gnome.desktop.background).
The describe command (e.g. gsettings describe org.gnome.desktop.background picture-options will list all possible values of a given key.
Update (January 1st, 2022): Gnome seems to have changed its configuration scheme with version 41. I’ve updated this post to reflect those changes. Thanks to Michael for pointing this out to me.