Painting With Texture in Photoshop

I recently learned how to import my own gesso texture into Photoshop and paint with it (see previous post here for full image). Some of you Photoshop pros are now saying something like "well, duh", but for me it was a big step forward. It's also much easier than I thought it would be. I am working with Adobe CS4, so I don't know how closely the following applies with newer or older versions.
STEP ONE was to chose a gessoed masonite panel- the type I usually prepare for my oil and acrylic paintings. I took black acrylic paint and with a sponge, worked paint down into the textured surface. I wiped most of it back out with slightly damp paper towels so that the deep texture retained the paint but most of the high texture peaks were wiped clean. I then scanned this 8" x 10" panel on my flatbed scanner at 600 dpi.

detail of my gessoed texture

With this scan now open in Photoshop, I adjusted the levels to exaggerate the contrasts a bit, pushing the darks and lights further apart. Next, under the EDIT tab at the top of Photoshop, scroll down to DEFINE PATTERN and click it. A box will come up with a thumbnail of your new pattern and a prompt to name it. Click OK and your pattern is now saved in the textures section of your Brushes Palette. To paint with this new texture, simply open the brushes palette and check the texture box. Click the word TEXTURE and your current selected texture will show up. To the right of your texture thumbnail is a small arrow pointing down. Click it and the textures in this palette will pop open. Your newly scanned texture will be at the bottom of the list. Select it and you are ready to paint with it.

Things to keep in mind when painting with texture:
If you want your texture to echo exactly what you have scanned and mimic a real gessoed board, DO NOT CHANGE THE SCALE SLIDER after you begin to paint. If you do, the size of your texture will not be consistent across the canvas.
You can choose to paint either the highlights or the valleys of the texture by leaving it NORMAL or by selecting INVERT. Normal will paint the "high" points of the texture much as with drybrushing and if you select invert, the paint will fill in the low points of the texture and leave the high spots relatively paint free. I found this to be very effective when I wanted to "glaze the shadows" without killing my texture. Keep in mind that when switching back and forth between the two, it is easy to forget and you may end up painting your highlights in the depths and the shadows on the peaks of the texture. I decided that INVERT would be for darks and normal would be for lights, so I could keep it straight in my mind.
Also, the depth slider allows you to determine how prominent or subtle you want the texture to appear. I found I liked the texture depth at about 70-75%. Using the OTHER DYNAMICS setting in the brush palette also is incredibly useful in order to take full advantage of your Wacom tablet capabilities, as it allows for softness at the edge of brush strokes, but that is fodder for another post. I hope this makes sense. if you have any questions after having tried this out for size, just shoot me an email or comment.