My initial reaction was to think about dealing with dirt. Ever try to maintain grip on a very smooth surface covered with a thin layer of dirt/dust? On fingers

My initial reaction was to think about dealing with dirt. Ever try to maintain grip on a very smooth surface covered with a thin layer of dirt/dust? On fingers, this stuff slides into the 'crevasses' of the print. Extremely pseudo-science, but in my 2 minutes of thinking seems like it could be worth a thought. I'm sure those scientists used clean hands on their testing papers.