I sent a 1960 Topps card to Mossi to be autographed - it came back in about a month signed in blue ink around his neck and really through the darkest part of the card.
I think the scan ended up a little lighter than what the card actually looks like in-hand - but I wasn't planning on sending the card to the 87-year old former big leaguer until I realized I'd rather have it signed sooner than never.