Ubuntu – How to change the purple background color of the lock screen on Ubuntu 17.10

customizationgnomelock-screen

Recently I installed Ubuntu 17.10 which comes with Gnome as the default DE and I like it a lot but cannot figure out how to change the purple background of the lock screen (when typing in the password).

lockscreen image

I've tried reconfiguring GDM but it seems to be different and it only affects the login screen.

If there is no solution I'm interested in ANY workaround because this purple drives me crazy but I don't want to drop GNOME entirely just because of this. Any help is highly appreciated.

Best Answer

From these steps here, you can change both the image and the background colour:

  1. Move your favorite image to /usr/share/backgrounds:

    • It's better to move the image you want to set as login background to system pictures folder: /usr/share/backgrounds. To do so, open terminal via Ctrl+Alt+T, then either run command:

      sudo cp /PATH/TO/IMAGE /usr/share/backgrounds/

  2. Edit the css file that define GDM login background:

    • Open terminal (Ctrl+Alt+T) and run command to edit file /etc/alternatives/gdm3.css, which is linked to /usr/share/gnome-shell/theme/gdm3.css:

      # Make backup first before editing
sudo cp /etc/alternatives/gdm3.css /etc/alternatives/gdm3.css.bakup
sudo nano /etc/alternatives/gdm3.css

      enter image description here

  3. When the file opens, go to menu (right after ‘Save’ button) -> find and find out following section:

    #lockDialogGroup {
  background: #2c001e url(resource:///org/gnome/shell/theme/noise-texture.png);
  background-repeat: repeat; }

    change the lines into:

    #lockDialogGroup {
   background: #000000 url(file:///usr/share/backgrounds/Aardvark_Wallpaper_Grey_4096x2304.png);
   background-repeat: no-repeat;
   background-size: cover;
   background-position: center; }

    Replace Aardvark_Wallpaper_Grey_4096x2304.png with your picture file name, and or change the hex colour code ##2c001e to the color of your choice.Here I used black.

    enter image description here

Lockscreen background:

enter image description here

Note: Backup all files before changing them

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