That's a really great article that brings some solid facts to the question. That guy did his research.
Thanks for sharing. This is a well-written and well-presented account of how mass-produced woodprint paintings show noticeable change between early- and later-printings.
They kept running editions off the original wood plates but the plates slowly wear and because of that colors changed from edition to edition. My father bought a 3rd edition print in the 60's when he was in the navy stationed in Japan. It's a bit muted, especially in the sky compared to the first runs I have seen in museums.