I rarely use pictures on my background wallpapers and like to use simple colors. There doesn’t appear to be an option in gnome-tweaks to allow me to attain this. It needs to be done from the command line.
gsettings set org.gnome.desktop.background picture-options 'none'
gsettings set org.gnome.desktop.background primary-color '#009999'
gsettings set org.gnome.desktop.background color-shading-type 'solid'Other options for graduated tints:
gsettings set org.gnome.desktop.background picture-options 'none'
gsettings set org.gnome.desktop.background primary-color '#000000'
gsettings set org.gnome.desktop.background secondary-color '#009999'
gsettings set org.gnome.desktop.background color-shading-type 'vertical'