Okay, first open your texture in Photoshop.
For example, I made this:
Then, click on the “Channels” tab.
Click on “New Channel” or this button right here:
Now you should have it like this:
Now, press SHIFT + F5, and a menu like this should pop up:
BUT! MAKE SURE THESE ARE WHITE AND BLACK:
Then click ok, and you should have it like this:
Now you must click on that eye to enable all channels!
After you’ve done those, compile your texture into .vtf format.
Then open the .vmt, and add “$selfillum” “1”
If you don’t add it, the texture simply won’t glow in the dark!
Ask if something wasn’t clear.