Here's a simple, from basics, texture tutorial that reviews how to reset the settings for grainy brushes in Painter 7. 

Dry Media & other grainy brushes

1. Open a new canvas in Painter 600 pixels x 600 pixels (Cmd/Cntrl-N).
2. Put the canvas in screen mode (Cmd/Cntrl-M).
3. Open the Papers section of the Art Materials palette.
4. Select the paper texture called Dry Cracks.
5. Click on the Brush Category (left) menu in the Brushes palette.
6. Select the Dry Media Brush Category.
7. Click on the Brush Variant (right) menu in the Brushes palette.
8. Select the Artist Pastel Chalk Brush Variant.
9. Make some brush strokes on your canvas.
10. Check the Invert Paper check box in the Papers section.
11. Now make some more brush strokes next to the first strokes you just made.

The way that a brush behaves, including it's interaction with paper grain, is specified in the Brush Controls palette. Open the General section of the Brush Controls palette. Notice that the Artist Pastel Chalk has a Method setting called Cover and a Subcategory setting  called Grainy Hard Cover. The inclusion of the word "Grainy" in the Subcategory setting means that the Artist Pastel Chalk is an example of a brush that interacts with the paper grain. All brushes that interact with paper grain (which includes all the Variants in the Dry Media Category) have the word "Grainy" in their Subcategory setting.

Notice that there is not a big difference between the brush strokes with and without the Invert Paper checked. The following adjustments will give you much better interaction with paper.

12. Open the Well section of the Brush Controls palette.
13. Check the Brush Loading check box.
14. Reduce the Resat slider from 100% to about 90% (this value is not critical).
15. Make brush strokes on the canvas.
16. Invert the paper grain (Invert Paper check box in the Papers section of Art Materials).
17. Make more brush strokes next to the ones you just made. Note the difference compared to the earlier strokes.
18. Reduce the Grain slider in the Controls:Brushes palette from 23% to about 10%.
19. Open the Brush Size section of the Brush Controls palette.
20. Increase the Size slider from 10 to about 29.5.
21. In the Papers section of Art Materials increase the Contrast slider from 100% to 200%.
22. Make brush strokes on the canvas.
23. Invert the paper grain (Invert Paper check box in the Papers section of Art Materials).
24. Make more brush strokes next to the ones you just made. Note the difference compared to the earlier strokes.
25. Drag the cursor in the Saturation-Value Triangle of  Colors section of Art Materials to the right.
26. Pick a color in the Hue Ring of the Colors section.
27. Make brush strokes.
28. Now pick a color on the opposite side of the Hue Ring.
29. Invert the paper grain.
30. Make brush strokes over the top of the ones you just made.
31. Play with colors and inverting the paper back and forth.

The adjustments that you made here in the Well section of the brush Controls Palette and in the Grain slider in the Controls:Brush palette are adjustments I recommend for every Grainy brush in Painter 7. The exact values are not important. Play with the sliders in the 
Well section and see what effect, if any, they have. Painter 7 remembers changes in these settings from one session to another. Every time you open Painter the settings for each Variant will be as you last left them. If you ever want to return to the default settings (when you first installed Painter) you can always select Variant > Restore Default Variant in the Brushes palette.

Jinny
__________