Etching Zinc with Copper Sulfate Mordant Test 10

Test Summary
This test will determine how a zinc plate airbrushed with Z-Acryl aquatint reacts to the Copper Sulfate Mordant. I am observing how well the aquatint holds up in a step etch test using Z-Acryl stop out as a resist.

Date: May 5, 2011
Researcher’s Name: Chelsea Mullins
Plate Material: .040 Zinc
Plate Size: 5 in x 7 in

Plate Preparation
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 dried BIG in the hotbox for 25 minutes or until it was smooth to the touch without any tack. I drew with an etching needle and placed the plate in the Copper Sulfate Mordant for 5 minutes. I degreased the plate again and applied a Z-Acryl aquatint in 9 passes following the standard aquatint procedure. I placed the grounded plate in the hotbox for 20 minutes. The aquatint was satisfactory but I stored the plate covered with a rag. The rag smeared the acrylic aquatint particles. Therefore the etched aquatint does not have the clarity it should in the printed proof.

Etching Notes
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
Initially I etched the plate for 5 minutes with a hard ground applied to create linear details in the large hand and figures. I applied an aquatint in 9 passes and dried the plate in the hotbox. I placed the aquatinted plate in the Copper Sulfate Mordant and every 3 minutes I removed the plate and placed it in a bath of water at room temperature. I used a non-abrasive sponge and gently wiped away the etched particles from the lines of the zinc plate. I removed the plate from the water 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 Copper Sulfate. I repeated this same process for a total of 15 minutes.

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 20 minutes. I scrubbed at the ground with Simple Green and a toothbrush until it came off.

After Bath Evaluation
The plate etched well but I should have given the aquatint a couple more minutes in the mordant to create a rich black.

Chelsea's Plate

Chelsea’s Plate

Inking Methods
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: 20 Minutes
Press Blanket Setup: Sizing catcher and pusher, 6.5 pressure, Small Takach Press

Test Conclusion
The step etch created great results. Now I know that putting a rag on top of the aquatinted plate creates some interesting textures.

Printed Images

Chelsea's Print

Chelsea’s Print