Step 1 --> Go to Layer --> New Adjustment Layer --> Levels.
Step 2 --> You can give the layer a name if you like, or just hit on 'Ok' like I do.
Step 3 --> Type in your input levels. I'm going to use 40 | 1,1 | 230.
The page itself has very light colours, therefore I'm not going lower then '230.' Because of this, there's still
'dust' on the edges of this page. Clean it by hand by either using the 'Polygonal Lasso Tool' or the 'Eraser Brush'.