Cant paint on level adjustment

[WalkInVerse]

With photoshop this is pretty straight forward and I do not know what I am missing.  I have a level adjustment and I slide the dark side in.  Now I want to paint part of it back.  If I use black or white it just leaves gray streaks.  Please see videocast.  What am I missing?

https://www.dropbox.com/s/gjuq2zymnnkl3fc/Recording %23134.mp4?dl=0

[GarryP]

One thing I noticed is that when you have White as the selected colour - or when you select White after using Black - your RGB sliders don’t show what I would expect. At first they’re at 128,128,128, then later they’re at 0,0,0. That could be causing the problem, or be part of it, but I don’t know why it’s happening.

Also, have you tried changing the Opacity of your brush? We can’t see what it is from your screencast. (If you don’t know what’s important, screencast everything.)

Either way it looks like the grey is coming through from the background image, as I would expect, but there’s something not right, or I’m not looking at it right.

[Lee D]

@WalkInVerse As well as making sure the brushes colour is set to 0,0,0 as @GarryP suggests. Can you also try ungrouping the layers and then try painting on the Levels adjustment again.