I just cut stuff and either fail or not, cutting paper and what not has lead me to wire edges and other stuff... try getting through service with a knife duller than a spoon, scary stuff.
Cut the gum strip cleanly off of a very thin cigarette paper, then stand another paper up on it's end folded and see if you can slice it half clean with one swing.
I listen to the knife as i run my finger tip across the blade at various points. Sound is good. Danger is fun. Blood is bad. I agree with the other guys...nothing better than to test it on the line.
I cut a paper towel. I hold the paper towel between thumb and index finger and make slices down the paper towel. When it's very sharp, I can cut across the paper towel instead of down the paper towel Or I use receipts (the thin printed waxy paper kind), envelopes or the brownish grey paper that people use when shipping stuff to you. Got lots of that! But the paper towel shows me the best how sharp the knife is.
I use yellow pages paper.. there should be one around. thin enough, for cutting through sheets.. How it cuts ( eyes) Sound ( ears) adn feel of the cut for smoothness ( touch) adn if you really want to see how good it is, should be able to cut through a corner of the whole phone book.. smoothly in one push cut; with thumb on the spine for more push power. ( definitely not a pinch grip)
Yellow pages ....Also good for stropping.
You have to engage more than one of your senses to do anything well.. most applicable for sharpening too...
Eyes.. smoothness of cut adn the cut on the paper
Ears: sound of the cut.. Coarse sound of smooth and quiet sound
Touch: Feel how it glides across the paper. Rough or smooth....
Thanks for the advice so far.Now I'll have a use for that thing!Yellow pages ....Also good for stropping.