In Thunderstorm Beneath the Summit, how is the Impressions discussed?
Soon after publication the blocks were slightly damaged with the loss of one of the brown dots below the summit and the end of the 'hitsu' ('brush of') character from Hokusai's signature. Impressions made before this have "continuous blue down the sky, wiped lighter across the middle, so making clear the entire shapes of the cumulonimbus clouds - rather than leaving a wide band of un-inked sky across the centre and thereby losing their tops."In a later impression the publisher introduced some significant changes.  The sky is now rendered in purplish greyish with a band of yellow at the top. The flash of the lightning bolt vividly silhouettes a group of pine trees at the foot of the mountain, cut from a new block, making them appear close to the viewer.
Hokusai