Bumpy towel material of washcloth, rolled wet towel, and dog's bed are made by microdisplement and adoptive subdivision surface modifier in Blender2.78.
If you want to apply the material to others, don't forget to set "experimental" in render > render > feature set, and apply subdivision surface modifier and enable "adoptive".
Thank you, thank you very much, you added a lot in my studies of materials and lights .. really good, congratulations.
genial!