Tuesday, March 20, 2012

Printing as liquid technology

A good old story tells us that the volatile years of the late eighteenth/early nineteenth century represent a moment of explosive growth in the market for printed materials. Greater numbers of men and women in Europe were able to read. Participation in coffee house culture and other bulwarks of the "bourgeois public sphere" created avid desire for newspapers, pamphlets and other, far less learned printed materials. And, thanks to the rupture in censorship during the French Revolution, new, radical or just risqué printed materials were readily on offer.

But, that late Enlightenment period sees dynamic changes in printed form and content alike. Aiming to capture the dramatic contrasts of light and dark achieved in the famous "candle-lights" of his friend Joseph Wright of Derby, Liverpool experimental Peter Perez Burdett, for example, developed (well, he said he invented it, but ...) a method of aquatint printing. In Burdett's process, rosen would be distributed across a copper plate, then heated to form tiny chemical indentation in the plate capable of bearing ink, which would then be pressed onto the dampened paper to read as the dark, velvety textures necessary for rendering Wright's works. "Impressions chemically wrought" as Burdett's prints were described at exhibition in the early 1770s.

For the scale, speed and ease of production requisite to addressing modern mass audience, few period methods could rival the new technique of lithography. And, so that we could all learn more about liquidy processes of subtending that technique, our class made a visit to the well-equipped studio facilities at a nearby university. There, two graduate students (Hideki, who stands in profile on the left above, and Aanchal who appears in the photos below) gave us some practical demonstrations.

The crucial principle of lithography is the chemical resist between oil and water. Invented by musical-printing entrepreneur Aloys Senefelder in the mid-1790s, so Hideki told us, the traditional lithographic process requires a finely smoothed limestone surface, which can be treated for printing, then ground down and re-used. As you can probably guess from the examples on metal work table at left, these blocks are extremely heavy! Once the limestone surface has been made flush, the image-maker draws or paints onto the stone with oily media. As you can see from the example here, our class collaborated on this masterpiece using waxy crayons and a range of other mark-making instruments.

Throughout the process, reinforcing the resists between oiliness and wateriness is critical. For, after the ink is set out and prepared for rolling ...

... the print-maker applies a solution of nitric acid diluted in gum arabic onto the stone. As Hideki explained, the acid solution needs to vary according to the tonal qualities of the image. A higher proportion of acid should be mixed into the areas of the design that are to read as darkest. But, as we see at left, the application of acid and gum effaces the design.
Here, Aanchal is explaining how, for the process to work, the stone must constantly be kept wet as the greasy design attracts the oily printer's ink rolled onto the stone, while the untouched zones of the image retain their watery resist to the oil.
Here, Hideki and Aanchal are working together to keep the chemical action on the stone in order. First, Aanchal wets the stone with water. Then, Hideki rolls on the ink.
Next, a sheet of paper is affixed to the stone and rolled through the press. I think you can understand why everyone would want to get involved in the fun!

Here are some awesome examples of etched states from Aanchal's notebook.

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