(Did you mean a fanzine named Twiltone?)
Twil-tone (usually misspelled twiltone or twilltone) was a brand name for a soft, fuzzy, thick mimeograph paper that many faneds preferred because it was very absorbent, so ink dried quickly, reducing the chances of set-off and the need for slipsheeting. It also came in many colors.
While not everyone liked it, it was considered very fannish. There were other brands, such as Fibertone, but fans called them all “twiltone.”
A lost technology, it became a minor object of worship among the most hard-core mimeographers in fandom.