I buy old papers and have been through a variety of brands, most no longer made. Sometimes it's devilishly hard to tell, in the dark, which side is the emulsion side because both 'feel' the same. Thus, cutting off a tiny piece and looking at that piece in the dark does not answer the question for the rest of the sheets. What to do?
I have found a way to tell which side is which and this information might help those finding themselves in the same predicament. In the dark, I hold a piece of paper next to my ear and lightly rub my (clean!) index finger across the surface. Then I turn the paper to the other side and do the same. There ALWAYS is a difference in 'pitch'. Now all you have to do is find out which pitch corresponds to the emulsion side (easy with a tiny piece in the light) and use that aural directive to answer a future question about which side is which. It's an easy, hassle-free way to find a modicum of sanity when such frustration prevails. - David Lyga