CQ26: 南方録 sais that there is nothing more important than the 墨跡 (ink traces), but there's evidence that in 利休's time, they were not the most frequently used type of scroll.
墨気: Prima facie the impression of aliveness of a line; but later idea that carbon molecules are aligned thanks to the 気 of the writer.
➡️ Zen priest 大森曹玄 published a book in the 80s with microscopic images comparing Zen master's calligraphy with amateurs. However, the difference in those photos probably has more to do with the ink and how it was being ground.
墨跡: ink traces, a poetic word for calligraphy that captures the idea that the spirit of the writer lives in the writing.