Originally Posted by
Captain Morgan
Kyle's ring subsequently didn't have the yellow weakness, but it also didn't have the AI which came standard package to the rings before and since. So he lacked things like auto-shields or a super computer that would already have that kind of information to reference. It added to his whole "rookie flying by the seat of his pants" vibe.
As such, I'd assume a Lantern of any other era can just say "ring, make Kryptonite" and the ring will reference the Krypnonite file, and that's it.