Measured on a Tektronix 2235 oscilloscope to demonstrate that a Commodore 64 typically outputs a bright pixel on the extreme left of the image (normally hidden by overscan).  The horizontal sync pulse and colourburst are visible to the left and centre, and the bright pixel is visible just right of centre.  The remainder of each line is completely black, as set by simple POKE commands.
<a href="//commons.wikimedia.org/wiki/User:Parrot_of_Doom" title="User:Parrot of Doom">Parrot of Doom</a>
<span class="int-own-work" lang="en">Own work</span>