My brush strokes won't reach full opacity, how do I remedy this?

[TRXIII]

In the attached image, the vertical dark stroke was done with my mouse, not even my pen tablet, as you can see transfer is turned off. The brush opacity and layer opacity are all at 100%, yet you can still see the layer underneath beneath the stroke.  I'm using version 22.1.1

[Jeff Arola]

If all the Brushes you try are like that, then i would suggest resetting the Brush Tool by right clicking on the Brush icon in the tool options bar just below Edit and clicking on Reset Tool.

If that doesn't work then photoshop preferences reset may be needed:

https://helpx.adobe.com/photoshop/using/preferences.html

[Trevor.Dennis]

You can only really test issues like this with the plain vanilla presets.

It looks like you are using one of the Chalk presets, and they are sampled at 50% opacity.