Copperplate Photogravure Process

COPPERPLATE PHOTOGRAVURE PROCESS:

Once the photograph is taken, it takes a series of steps to transfer the image onto copper and transform it into a permanent plate. Once the plate is made, it is inked, wiped by hand, and printed on a traditional printmaking press. The process is very tedious, but a successful photogravure plate is always worth it!

1) Sensitizing gelatin tissue with Potassium Dichromate

2) Exposing a transparency (a positive, reversed enlargement of the photograph) onto the gelatin tissue

3) The exposed image on the tissue

4) Developing the image, where all of the unexposed gelatin washes away

5) The developed image. The gelatin serves as a resist, which will etch in different depths depending on the thickness of it. For instance, the lightest areas in the resist will etch the most, thus becoming the shadow areas.

6) Etching the copper plate in ferric chloride. Photogravure uses different strengths of ferric chloride, beginning with 46 Baume (the weakest) and progressing to 39 Baume. The timing of each bath depends on the tonality of the image, so I constantly keep an eye on the Stouffer scale. The average etching time is about 30 minutes, depending on the density of the transparency, exposure time, air and ferric chloride temperature, and humidity.

7) Once the image is etched into copper it is not light sensitive anymore. Intaglio ink is applied to the entire plate and wiped off by hand. The wiping technique determines the final look of the image.

8) The last step is printing on a press. Different papers can be used, but I prefer delicate Japanese Gampi or Magnani Pescia, a smooth and high quality intaglio paper.