Oddness and lavish mid-Victorian colour printing did seem to go together, yes: https://books.google.ie/books?id=SugpRWf_FB4C&pg=PA35&lpg=PA35&dq=%22the+inventio

Oddness and lavish mid-Victorian colour printing did seem to go together, yes: https://books.google.ie/books?id=SugpRWf_FB4C&pg=PA35&lpg=PA35&dq=%22the+invention+of+tradition%22+%22any+method+of+colour-printing+subsequently+invented%22&source=bl&ots=Ne-uOhqRFR&sig=y4woaYEzLPKgLSbZBzYTV3DJF_g&hl=en&sa=X&ved=2ahUKEwjYp_Gj7qbfAhUCqXEKHbOwAzYQ6AEwAHoECAEQAQ#v=onepage&q=%22the%20invention%20of%20tradition%22%20%22any%20method%20of%20colour-printing%20subsequently%20invented%22&f=false https://books.google.ie/books?id=SugpRWf_FB4C&pg=PA35&lpg=PA... https://en.wikipedia.org/wiki/Vestiarium_Scoticum https://en.wikipedia.org/wiki/Vestiarium_Scoticum . Like the frilly initial letters it's clearly an archaising choice meant to hark back to early printed Euclids (see the one in https://www.c82.net/euclid/about/ https://www.c82.net/euclid/about/ ): part of the nineteenth-century craze for style revivals.