We wanted to determine if we can etch the plate for 15 minutes using the BIG hardground without under biting or foul biting. We stage bit areas of the plate, using Z-Acryl water soluble stop out solution, every 3 minutes to determine the quality and strength of the Copper Sulfate mordant.
Date: February 25, 2011
Researcher’s Name: Chelsea Mullins and 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. We dried BIG in the hotbox for 25 minutes or until it was smooth to the touch without any tack. Using etching scribes we drew through the ground and completed our image.
The Copper Sulfate Mordant consists of 50gm salt + 50 gm copper sulphate + 1 liter H20 stored in a plastic lidded container. We created a shallow bath in a plastic tray where we can place the zinc plate for etching. In this experiment the bath looked cloudy and had less of the typical greenish tint.
Timed Application of Mordant
Every three minutes we removed the plate from the mordant and placed it in a bath of water at room temperature. In the printed proof below we marked the time increments on the side of the print. Using a sponge we wiped away zinc debris in the etched lines. We removed the plate from the water bath and dried it. We applied Z-Acryl stop out solution to areas that we no longer wanted to etch. The stop out air dried for 20 minutes and we placed the copper plate back in the mordant bath. The total etch time was 15 minutes.
Removal of Grounds
The ground was removed by immersing the plate in a stripper bath of Arm & Hammer Washing Soda and water (100 grams/1 liter) for 20 minutes. Any remaining ground was removed using Simple Green and a rag.
After Bath Evaluation
Some false biting is apparent but not as bad as the previous test.
The plates were 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: Hahnemule Copperplate
Paper Soaking Time: 15 Minutes
Press Blanket Setup: Sizing catcher and pusher, 10.2 pressure, Small Takach Press
We achieved better results in this test. The thin marks with little variation that we created do not provide a clear answer to whether 15 minutes is enough time achieve dark hard ground lines.