Optically-coated picture framing glass works so-so in our admittedly foggy coastal climate here. A
practical substitute for a true antinewton textured glass is simply to use a sheet of three mil or five
mil frosted mylar (frosted both sides) between the upper glass and the back of the neg. Just inspect it first on the lightbox for dust or blemishes. You can get sheets of this in art stores. It only slows the speed of printing about a third of a stop. Anti-newton powders are available from the same outfits who sell scanner fluid, but be careful how you use these - there's a distinct technique, so
you'll want to practice on a scrap negative first. I don't like to use them unless every other option
fails - like, for example in a masking sandwich where I can't avoid base-to-base film registration.
But most of you will never encounter a situation like that.