This test will determine if 30 seconds intervals is enough time to notice any visible tonal difference in step etch created by the Copper Sulfate Mordant.
Date: April 15, 2011
Researcher’s Name: Melissa Mandel
Plate Material: .040 Zinc
Plate Size: 5 in x 7 in
The plate was degreased with soy sauce that was rubbed onto the zinc plate using a piece of rolled felt, rinsed and then dried with a clean rag and blow dryer. The BIG was squeezed from the tube onto a clean, glass inking slab, spread with a knife and rolled up using a 4″ diameter, medium hardness brayer. Several thin layers of red BIG were rolled across the surface of the zinc plate, building gradually to the point that the zinc did not sparkle through the ground. I rolled BIG on the edges of the plate and applied Z-Acryl stop out solution to any areas that I might have missed with the ground. I dried BIG in the hotbox for 25 minutes or until it was smooth to the touch without any tack. I used an etching scribe to create a simple line drawing that I could follow after I aquatinted. I etched the plate for 3 minutes. The ground was removed using a stripper bath of Arm & Hammer Washing Soda and water (100 grams/1 liter). I followed the above degreasing procedure and applied a Z-Acryl aquatint in 9 passes with a standard airbrush. I dried the aquatint in the hotbox for 20 minutes and prepared to etch the plate.
The Copper Sulfate Mordant consists of 50gm salt + 50 gm copper sulphate + 1 liter H20 stored in a plastic lidded container. I etched the plate vertically in a plastic file bin. I used a plastic letter holder that fits into the file slots to keep the zinc plate in place during etching.
Timed Application of Mordant
Every 30 seconds I removed the plate from the mordant and placed it in a bath of water at room temperature. I removed the plate from the bath and allowed it to air dry before applying stop out. I applied Z-Acryl stop out solution to areas that I no longer wanted to etch. The stop out air dried for 20 minutes and I placed the zinc plate back in the mordant bath. I repeated this same process for a total of 5 minutes. The stop out times are indicated on the print below.
Removal of Grounds
The grounds were removed by immersing the plate in a stripper bath of Arm & Hammer Washing Soda and water (100 grams/1 liter) for 30 minutes. I scrubbed at the ground with Simple Green and a toothbrush until it came off.
After Bath Evaluation
The etch appears normal but the zinc produces heavy sediment as it etches in the Copper Sulfate Mordant.
The plate was inked with unmodified Graphic Chemical & Ink Co. Bone Black Etching Ink #514. The ink was carded on with mat board scraps, wiped with used tarlatan, and then palm wiped.
Paper Type: Hahnemuhle Copperplate
Paper Soaking Time: 15 Minutes
Press Blanket Setup: Sizing catcher and pusher, 10.2 pressure, Small Takach Press
The tone of the printed proof appears to be muddy and irregular. Despite multiple stop etches only two tones are visible. I suspect that I sprayed the aquatint unevenly and too thick which would explain the irregularities of this proof.