Thursday, November 14, 2013

Chemigram to photogravure (for printmakers)

figure 1
(Franco Marinai sends a guest post)

I do my chemigrams on 8x10" high contrast orthochromatic film, not on photo paper, since I will port them to photogravures when I'm finished. I use undiluted Golden varnish, bleach, Dektol, fixer, warm and cold water.  The transparency of the film allows me to reproduce the chemigram on a copper plate and ultimately ink it, wipe it, and print it on a high-pressure press as an intaglio print, thereby giving me the three dimensionality and subtle tactility of an etching.  But I will do this following the more demanding photogravure process, which is best known for the elegance of its continuous tone reproduction and its exceptionally intense blacks.  This will ensure fidelity to the mesmerizing graphic qualities of the chemigrams.

Fig. 1 shows the final rinse of an 8x10" chemigram on orthochromatic film.  I use hard water, rich in magnesium and calcium cations, from the well in the square outside my studio in Serrazzano, Italy.  Serrazzano is a small medieval village on a hilltop 25 miles south-west of Volterra.

figure 2
Here (fig. 2) the transparencies have been cut and masked in preparation for the gelatin exposure in the vacuum frame.  The chemigram of the one on the left was started with immersion in bleach, while the one on the right started with Dektol.

figure 3

After the gelatin has been exposed, transferred to the copper plate, and developed in warm water, the plate is covered with a fine layer of rosin (aquatint) and readied for etching (fig. 3).

figure 4

The plates have been etched for twenty minutes in ferric chloride (fig. 4) and cut to the size of the transparencies (7x10").

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This is the first proof of the two plates: Side By Side (2013).  Typically I print an edition of six plus an artist's proof.  Here are a few more photogravures, all printed from individual plates and produced using the same technique.

Marinai, They Do Not Think The Same, 2013

Marinai, Comics, 2013
I can be reached through my website,, or you can post comments below.  For a detailed discussion of the photogravure process, visit Lothar Osterburg's site.

                                                                                                                       - Franco Marinai