I assume it's Ritta Nakanishi's 1841-1929 volume:
Thanks, that is indeed where the Pinterest and blog pictures seem to come from. Bit of a "sticker shock" moment on that price for a used copy
There’s also an Osprey book out for it but I haven’t got it yet.
Actually in their sale at the moment! I picked it up last week, it is a good starter.
Covers the Boshin War and Satsuma Rebellion so 2 different uniform eras in the colour images. The modernisation prior to the Boshin War is also covered in the text and b/w images.