Personally, I've never seen it.
I own Mad magazine from #1 to the present.
You can actually see the changes.
1952, a very yellow-brown. By the 1970s still a tinge of yellow, even though I bought these off the stand.
And how brittle.
Some of my '60s paperbacks cannot be read, because they just crumble. Plus the backing falls apart and you're left with mere pages in your hand.
Not saying you aren't an expert, just never seen such a specimen.
Best of luck to the buyer, though.
Well, “Mad” magazines do have a pretty strong tendency to yellow. I don’t think their paper was terribly white to begin with, even judging from my memories. I have a batch of them from the late-50s/early-60s in decent shape. But they are in the light-to-middle-yellow spectrum. I bought them at an antique mall from a guy who purchased them new, up in Minnesota. The paper was better preserved than the similar examples I’d gotten down here in Texas, which almost always very yellow or worse.
But I do have some 1940s/1950s comic books with solid white to bright off-white paper. I also have a “G-Men” pulp magazine from 1939 with amazingly bright paper. Not yellow at all. Looks like a copy that has never been read, in terms of its handling, as well. And pulp magazine paper was the cheapest, most acidic paper around, most prone to yellowing and browning. But somehow, it was stored in an ideal situation, temperature, and lack of humidity.
Yeah, paper quality has always been a really, really big thing for me. I’ve had three and four copies of certain individual items, with all of them ranging the whole spectrum, from white paper to yellow to beige to brown to dark brown!