Engines of Our Ingenuity

No. 791:

by John H. Lienhard

Today, a young man sees possibility in a laundry list. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

One day in 1795, Alois Senefelder's mother called him from his workshop. She was sending out a load of laundry. She needed paper to record the clothing items. Senefelder didn't have any, so he penned the list on a flat stone with a grease pencil.

He was 24. His father had been a noted German actor. Senefelder wanted to go into theatre, too. He'd already written a play that did pretty well. He'd made a little money with it.

But then Senefelder's father died, and he was left poor. Maybe he could make a living by writing, but it cost too much to have material printed. So he did an astonishing thing. He set out to invent means for printing his own works. And, while he was in his workshop, his mother asked for that laundry list.

We did two kinds of printing in 1795. In relief printing you create an image that protrudes from a plate. When you ink the surface, ink hits only the parts that stick out. Both typesetting and woodcuts work that way.

The second method is intaglio printing. You cut an image into a plate, ink the whole thing, then wipe the surface clean. Ink stays in the depressions and transfers an image to the paper.

Now Senefelder was about to discover a third method. He wanted to etch copper plates chemically. Then he had to make that laundry list. He used a limestone slab -- the kind printers mix ink on. He'd planned to try etching stone as well as copper.

He was about to erase the stone. Then, on a hunch, he etched the surface with acid. Sure enough, the grease pencil protected the stone. Words were left standing. The depressions were far too shallow to take ink. Yet, they did take ink.

Senefelder had stumbled on new means for setting off inked and non-inked regions of a flat surface. He'd found a way to make stone take ink chemically, not mechanically. The full chemistry of the process wouldn't become clear until long after his death. It's tied to the makeup of limestone and fatty acids.

We call the process "lithography." That's Greek for Senefelder's own term, "stone printing." And it was not simple. It took four years for Senefelder to get the process under control.

By the time he died in 1834, lithography had become the dominant means for putting pictorial images and musical scores into books. Senefelder had passed from seminal inventor to innovator. He gave us a series of lithographic presses, each one better than the one before it. He improved the chemical process.

And what of Senefelder the writer? Well, in 1819 he wrote a wonderfully clear textbook on lithography. And, as a writer, he kept right on serving printers -- down through the 19th century.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Jennett, S., Pioneers in Printing. London: Routledge & Kegan Paul Ltd., 1958, pp. 91-105.

Weber, W., A History of Lithography. New York: McGraw-Hill Book Co., 1966. See especially pp. 9-25.

Senefelder, A., A Complete Course of Lithography. New York: da Capo Press, 1968.

Listeners near Houston, Texas, can see two early lithograph presses based on Senefelder's design in the Houston Museum of Printing History (713-522-4652).

The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.