Date: April 7th, 2016
Researchers: Katie St. John and Liv Stanislas
Room Temperature: 70 degrees Fahrenheit
Humidity, etc: Dry, No Humidity
Materials: 4″x 6″ Copper Plate 0.032 Gauge, Sodium Carbonate, Ivory Bar Soap, Guerra Titanium White Pigment, Linseed Oil, Water, and Graphic Chemical Bone Black Ink.
We took the most successful ground from our last experiment (the sodium carbonate, shaved soap, Guerra pigment, and linseed oil formula) and attempted to replicate our results. We used both a freshly made ground and a two-week-old batch to see if there would be differences in their reaction to the ferric chloride, removal from the plates, and all of the same visual qualities we look for in a soap ground. We also looked into the composition of the Guerra pigment and which properties make it a successful replacement for loose titanium pigment.
Plate Preparation (surface prep, ground application, image making process, etc.):
Burnished out significant lines, steel wool sanded then Putz Pomade applied; Cleaned with 7th Generation Degreaser; degreased with soy sauce, backed with contact paper
Sprayed acrylic aquatint through an airbrush onto the plate, then heat-set the aquatint in a hot box for 20 minutes before adding soap ground, plate sat for over 1 week
Soap ground recipes: Sodium Carbonate ½ tsp, Shaved Soap ½ tsp, Guerra Pigment ½ tsp, Linseed Oil ¼ tsp
*Shaved soap was grated on a typical kitchen grater, smallest size grater available, and then crumbled by hand to a consistency of short-grain rice. The crumbled soap at this point is three weeks old.
Application of the shaved soap ground:
Both grounds mixed well and took to the plates easily when applied with brushes of various types. The older ground was certainly drier, but we reconstituted the ground easily with water.
When we were mixing the fresh ground, we changed the order in which we mixed the components and added the Guerra pigment last. The ingredients did not bind well without it, which led us to believe that the Guerra pigment acts as more than a visual aid for applying the ground. The most likely answer lies in the propylene glycol that acts as a binder in the Guerra pigment; it may act as an emulsifier in the soap ground as well.
Etching bath notes: 40 degrees Baume ferric chloride
Etched in horizontal bath with agitation every 2 minutes or so
Time in bath: 23 minutes
After bath evaluation
The two-week-old ground looked like a lot of it had lifted off in the etching process while the new batch looked like it remained mostly intact on the plate.
Removal of grounds (chemicals used and evaluation of effectiveness)
Removed residual soap grounds with 7th Generation degreaser and wiping with rags
The newer batch was stickier and harder to remove with 7th Generation degreaser.
Placed in stripper bath for 15 minutes to remove the aquatint
Placed in deoxidizer bath
Inking methods (type of ink used, modifiers, wiping/rolling techniques)
Ink: Graphic Chemical Bone Black with no modifiers
Tarlatan wiping with a short paper wipe to finish
Paper type: Hannemuhle Copper Plate Bright White, ⅛ sheet
Soaking time: 25 minutes
Press (blanket set up and pressure): Pelican Press with 2 sizing catchers; 0.8 pressure
Conclusions: The freshly made ground was able to achieve a good balance of tonal range, texture, and ease of application, while the older ground did not retain as much detail in the etching process and was not able to achieve the same bright whites. Because more of the ground fell off in the bath, the older ground had a more compressed value scale. This formula seems to work but definitely has a shelf life. Our next step may be to see exactly what that shelf life is and to continue pursuing soap ground recipes that use powdered soaps and detergents similar to Ivory Snowflake Soap.