[TUHS] UNIX Manual Cover Art Origins?

[segaloco via TUHS]

Good day everyone, I'm in search of a bit of esoteric information regarding published UNIX works.  Does anyone know of any of the tools, formats, practices, etc. used in producing the actual graphical covers of various published UNIX manuals?

Some that come to mind:

The alphabet blocks cover of the HRW V7 Manuals

The simple 70's Bell-style cover of the UNIX System III manual

The nice 3B-20 picture on the UNIX 4.1 manual

The grid patterns design on the UNIX System V documentation

The blue "big V" SVR4 manuals (given the time disparity, these could have totally different underpinnings)

Where I'm particularly curious is how these covers were actually set, defined, the image data to print on them stored, formatted, etc.  In other words, <???>:troff::covers:manpages where ??? may also represent more than just the specific tools/formats.  Anyone have the scoop on the actual raw materials and technologies used for preparing the covers and/or if any of those original assets, in their raw form, would potentially still exist somewhere?  To be honest, I am particularly interested in the original, highest fidelity possible image of the 3B-20 from the corresponding manual (https://commons.wikimedia.org/wiki/Category:Unix_Manuals#/media/File:UNIX4.1UsersManualCover.png) but am happy with any info illuminates what went into the actual physical production.  Thanks all!

- Matt G.

P.S. If it provides any leads, the closest thing I've found in actual document sources to material related to these aspects of physical publication are the files M.folio and M.tabs here: https://www.tuhs.org/cgi-bin/utree.pl?file=SysIII/usr/src/man/tools