Founders Grotesk was initially designed for headlines, but upon its first outing—in a newspaper—it was used at text sizes and performed rather poorly. The lighter weights were serviceable at best, but far from ideal. The bolder weights veer pretty close to disaster, almost clogging up completely. Perhaps with a bit of letterspacing and better printing it would only just be passable.
When Francesco Franci used Founders Grotesk (and Tiempos) for his wonderful redesign of IL: it was simply failing at text sizes with sub-optimal printing conditions. After discussing our options we decided the best fix was to make a text version of Founders Grotesk.