Standard A. and K Zildjians have a thin, water based polyurethane coating on them. K Customs, K Constantinoples, Armands and all Brilliant finished Zildjians do not have the coating.
Hmmm. That's probably one of the reasons I can't stand the sound of new As and Ks. Kcons are another story. I have 3 22" kcons and a pair of Kcon hats. Love 'em all. The current crop of A's sound ultra bright, pingy and strident to my ears. They mostly remind me of Sabian B8's with slightly better tone. Moist new K's are,... well they're just boring to my ears. Other then the Kcons, a number of Bosphorus cymbals, one Istanbul, and a Sabian medium thin Artisan, all our cymbals are either old K's or old A's. The A's are all late '40's thru '60's