This will be a rather longish and heavily pictured post about my first experiences with the photogravure process. My son and I have been going through it once now from start to finish, the results being unimpressive but instructive.
One word of warning: if you’re an experienced printer and don’t like to see amateurish behaviour and cruel use of materials, stop reading now!
That being said, we’ll start quite harmless:
These were easily made from the medium format negative on 5×7 inch Adox halftone sheet film, developed in Tetenal Eukobrom.
Another afternoon’s work was making the gelatin paper:
Using a picture frame, colored hot gelatin is poured onto wetted drawing paper. I had thought that drying the paper on the glass was a good idea, but it stuck to the glass even when dry.
These crooked fellows turned out to be useable, smoothing out in later wet stages.
Finally, we come to the copper plates:
Using Brasso, the already mirror finish copper plate is polished even higher.
They are brightened with a salted dilute acetic acid.
Earlier, I had sentisized the gelatin paper with potassium bichromate. Sorry, no photos while handling poisonous solutions and wearing a breathing mask and gloves 😉
Now for the exposure:
First the Aquatinta screen, then the sheet film positive are being exposed onto the sentisized gelatin paper under a head bronzing lamp. Exposure times were 15 and 10 minutes, respectively. The time for the positive may have been a bit short, as the resist turned out mighty light!
Adhering the exposed tissue to the copper plate was another occasion where I needed both hands and couldn’t photograph.
Development in warm water showed sloughing-off of the non-hardened parts of the gelatin resist.
Once all the soft gelatin has come off, the plate is transfered to an alcohol bath to dehydrate.
It is left to dry for a few hours before you can etch through the resist.
Etching in ferric chloride.
Inking the plate, you try to work the ink into the microscpic recesses created during the etch. We might have been wrong not to heat the ink.
You don’t want any ink in the highlights, so wipe it vigorously! This gets you:
… dirty hands. Or a lot of soiled latex gloves!
Now the last step, printing the plate, turned into a comedy of errors of sorts. We were eager to see some results on paper, but:
We didn’t have proper blankets for the printing press, just old bedsheets. This gave uneven pressure, resulting in
an uneven impression and a
At the edges, there was a hint of what I wanted the print to look like:
So, time to get some proper blankets for the press and to read up in the later chapters of “Copper Plate Photogravure”. Any hints from experienced printers that have made it this far through this rambling post are more than welcome. Are there any shortcuts that work?