I don't know what I did. But I full on lost the color black. Like I will have it on black. But it keeps drawing a gray color. I don't know what to do. I tried the color select thing. I tried dragging it by it self to the black. I tried using different tools. I tried restarting the program and my computer. Nothing works. I don't know how to fix this.

Which operating system and which version of krita are you using?
Which tablet do you use?
Are you painting with a mouse or with a stylus/tablet?
Does it happen with the b)_Basic-1 and b)_Basic-2_Opacity brush presets?
Does this happen with all brush presets that you use?
How are other colours affected?

Can you post a link to a full screen screenshot (.png) of the entire window, showing the layers docker and the status bar at the bottom, when this is happening?

Ok it's working now. I don't know it wasn't working before I reported this. But not it is working. Also thank you stranger for help. (And yeah I don't know how to use this site. So yeah I don't know if you will see this or not.)