How to add a texture over the entire screen (newbie to AE)

[Katie5EF5]

Hi, I'm into my second week working in After Effects (I'm a hobbyist so I have no formal training). I'd like to add a water-color paper texture over the entire composition (which is made up of multiple individual comps) but I also don't want to lose the color of the original, so changing the opacity doesn't achieve the effect I'm looking for. Basically I want the shadows that visualize the bumps of the watercolor paper in the image without sacrificing color shade too much. Is there a way to do this? And while I'm on here, does anyone have and/or know where I can find a high-resolution png of watercolor paper texture?

[Rick Gerard]

Put your watercolor texture on top of all of the other layers (layer 1) and then experiment with blend modes. Try Multiply and Overlay, then play with opacity. To see the blend modes as well as the switches columns in the timeline turn on the first two icons in the bottom left corner of the timeline.