I suspect there are few of hot pixels on my panel. As it is still under warranty and by the rules of my vendor I can replace a machine if panel has a 3 dead pixels on it, I'd like to check how many dead pixels there actually are. In Windows, there are plenty of simple applications that just fill the whole screen with different colors so hot/dead pixels are easily visible. Does something like this exists for Ubuntu?

3 Answers 3


This page just provides the white / black / red / green / blue screens to test your monitor: http://lcdtech.info/en/tests/dead.pixel.htm

  • Any reason to recommend this HTTP website over any similar web test? Webpages aren't typically saved for offline use and I feel that the answer is off-topic.
    – user598527
    Sep 29, 2020 at 10:22

open terminal and install:

sudo apt-get install screentest



right click on the screen to access the options for different test colors and patterns

  • this tool seems to be designed for CRTs and is not fit for checking dead/hot pixels. go with the web tool posted by @pba.
    – Lanchon
    Aug 19, 2023 at 2:46
  • It is perfect for dead pixels. Start the program, right click, choose blink and set the background color for red, then green, than blue. Because it is blinking continuously, a dead pixel will "jump out".
    – PeterB
    Oct 9, 2023 at 11:30

You could use GIMP Image Editor to make 4 images that are the same size as your desktop and color them red / green / blue / white.

Then open them in Image Viewer ( default picture viewer ).

Then dual click on the picture to get it full screen.

GIMP Image Editor is available from the Ubuntu Software Center

Following is a How-To for the visual learners.

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