It is not mechanically printed, those materials where hand drafted. I got some very old teachers in college during the 90s, and their hand-drawn flipcharts looked exactly like this.

Sometimes companies used to hire artists to finish this kind of material, but usually engineers at that time were pretty much capable of drafting this kind of presentation on paper, just with rulers, compasses, and the ocasional template rule.

White collar professions used to be way more embodied in the real physic world. Kids were trained on caligraphy and basic drafting techniques since elementary school.