What do we know about The Black River?

It has long been one of the references to printing, like printing being referred to as "a black art." It refers to the rivers of ink made up by rows of type on a page. When you tilt the page and look down the rows of type, the characters blur and you see only the rivers. But since the shapes of the characters all vary and some are tall while others have either vertical or horizontal elements, or long "below the line" elements, the rows do not appear to be solid black. They have darker and lighter areas. The most intensely black area is at the baseline, since every letter in the western world and most other character forms touches it. The darker area near the deepest black is referred to as "the channel." The gradually lighter areas that lie above and below the channel are "the shallows." The completely white space that lies between the rivers is the shore. German "black type" (Gothic Textura) is very sonsistent with a broad deep channel, very narrow shallows and pretty much no shores. But even within this dark area, it is possible to see different values of light and dark. It would be possible to manipulate this pattern with very subtle changes in the design of the type.

Gutenberg cast characters in two different sizes. It seemed to be an economy thing to switch from the first, larger size, to the second type that was used for the 42-line Bible. As it was, the Gutenberg Bible was two volumes of 600 pages each. Some bindings have split it into three volumes.

There were other things that Gutenberg employed in printing The Bible. He used a variation on a wine press of a crew-type as his press. He also formulated an ink out of boiled linseed oil and lampblack. The depth and permanency of that ink has not been surprassed. He printed nearly 200 copies, one-third of which were on calfskin vellum. It seems likely that page and paper size were determined by a mathematical process to decide the optimum size to be cut from a calf's hide.

Of the extant copies, I have seen the one at the Library of Congress, the two in the Gutenberg Museum in Mainz, Germany, and the two at the British National Library. I have the digital copy of the Library of Congress copy that John Warnock's Oxford edition produced.