Hi everyone! I hope you will find this information useful. I had a very hard time figuring out how to remove the shadow texture from cold pressed watercolor paper. Here is what I now do.

My scanner is a Canon 9000F MarkII

Scan the image twice, once right side up and one upside down. Rotate the upside down one 180 degrees so it is right side up.

Add both images to Photoshop.

Select both layers

Rasterize all layers

Then auto align both layers

Set the top layers opacity to about 50% and merge down

Edit if needed