A total lunar eclipse is rated on the Danjon scale: 0 is so dark the Moon nearly vanishes, 4 is bright coppery orange with a bluish rim.

The difference is Earth's atmosphere. Every ray reaching the eclipsed Moon has been filtered through our air, so dust and volcanic ash make it darker: the eclipses after Pinatubo erupted in 1991 were among the blackest ever recorded. Rating one is a genuinely useful naked-eye observation, and there is nowhere else you can measure the state of the whole atmosphere at once.