When I took my first rodent steps into the Big Rat Race, one of the first machines I encountered in my office was a huge beast which had the abnoxious penchant for emitting a pungent smell when it was called to work.
In those days, after the hand-drafted drawings were completed on mylar films, or tracing paper, the originals were passed through that stinky machine to make more copies. The maximum size that it could accommodate was A0. All the lines on the copies were blue, and the background also had a light bluish tinge.
Of course these days, giant-size photocopiers have rendered the ammonia printers obsolete. The copies are also no longer blue.
But the term “blueprint” is very much in use, especially figuratively in describing plans for making things in the future.