In this detail from my Pearl Dive Poster, here's how it looked when I first imported the red type "shadows" and the diver image, which are filled with flat color, no texture.
And here is how it looked when I changed the layer blending modes on the red type and diver to Linear Burn, which adds the texture of the underlying layers to these formerly flat areas.
I snagged the organic, grainy blue texture from a wood block print by Austin artist Eleanor Droll. Using content-aware fill and some rubber stamping, I eliminated the flowers. The roller marks in the upper left quadrant ultimately became the bubbles coming up from the pearl in the diver's hands!
I shot a piece of watercolor paper to use as a bckground. In the detail, the blue layer has some texture from the flower print, but blocks out the paper on the layer below with the layer blending mode set to Normal. On the right, the blue layer is in Linear Burn mode, which lets the paper texture show through and gives it the effect of actually being printed on the watercolor paper.
The client wanted a darker look to indicate that the event, previously held in the day time, was now a night-time event. So here is the "Night" version of the background texture (no grungy edge yet).
To help create the effect that the background is blue ink silkscreened onto rough paper, I added a mask that I made by lightly stroking (actual) paper with black chalk so that it accentuated the paper's texture. Then I scanned it, upped the contrast, selected a color range and made that selection into a mask.
A section of the scanned chalk on paper that I used to make the mask. Areas on the layer mask that are black hide the layer, white reveals.
FINAL, with the new "edgier" background.