using the watercolour filter increases contrast
I find the ‘Watercolor’ filter creates interesting dark and light areas in photos that might otherwise be a bit flat. I usually set the brush detail to fairly high (9); the shadow intensity to 0; and the texture to 1 or 2. It’s also helpful if you want to print a low res photo in a larger format. Blown up to about 4x, people commented about how ‘sharp’ this low-res photo was.