How do I stop openframe?

sudo pkill -1 -f openframe doesn’t seem to work.

Openframe runs as a node process, so if you want to kill it directly via the command line you can do so by killing node: sudo pkill -f node

Do you have openframe set up to autoboot? If so, it does a bit of trickery to make sure that no text displays on the screen between artworks. You can reboot the Pi, then press ‘n’ as soon as you see the welcome text in order to cancel the autoboot into openframe.

When it's in auto boot mode it's not possible to stop open frame for me. Shift c and Shift W doesn't work. I tried to hold 'n' during the reboot, but not yet succeeded after several attempts.

I wonder when shall I hold the 'n' key during the reboot?

When you reboot, you’ll see welcome text appear. As soon as you see the welcome text, press and hold ‘n’. Probably obviously, but make sure you’re using a keyboard that is hooked up directly to the Pi, SSH won’t work.