I made a set of six of these map-themed postcards, for a swap here at Mixed Media Club, and for patron rewards on Patreon.
To create the backgrounds, I used some pages from an old Mapsco, purchased in the clearance section of my favorite used bookstore. The key feature of these old guides is they have tons of pages that are nothing but street maps, so they’re very busy. Rather than use them as is, I decided to tone them with some color, to make them less “HI, I’M A MAP!”, and more background-like. Here’s how I did that: