Etching Zinc with Copper Sulfate Mordant Test 7

Test Summary
This test will determine how a Z-Acryl aquatint, applied to a zinc plate, reacts to the Copper Sulfate Mordant. This test will also observe how well the Z-Acryl holds up in a step etch test using either Sharpie or lithographic crayon as a resist.

Date: April 14, 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. I applied a Z-Acryl aquatint in eight passes across the plate following the studio’s basic aquatinting procedure. However I allowed the Z-Acryl spray to come out of the airbrush too quickly. I expect that the aquatint will be course but not unusable. I used Sharpie and lithographic crayon to create two different resist. On the bottom of the plate I depicted a curvy rope, cowboy hats, and birds with the lithographic crayon. In the middle of the plate I drew a rope with the Sharpie. These symbols should protect the plate from being etched and leave these areas white. I also painted small symbols with Z-Acryl every two minutes. This process coincided with the step etching. The purpose of the symbol was to preserve the tone of the previous etch. When the step etch is completed I will be able to understand the amount of time is needed to create a specific value.

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. I noticed salty looking deposits forming on the zinc plate’s surface but they did not seem to effect the etch.

Timed Application of Mordant
Every two minutes 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 15 minutes. The etch 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 20 minutes. I used Simple Green and a rag and scrubbed at the ground until it came off.

After Bath Evaluation
The aquatint did not fall off over the full range of 15 minutes and I could possibly push it to 17 minutes. The Sharpie and the lithographic crayon worked well.

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: 10 Minutes
Press Blanket Setup: Sizing catcher and pusher, 10.2 pressure, Small Takach Press

Test Conclusion
Even though the aquatint is coarse I still consider this print a success. The copper sulfate is proving to be a an excellent mordant for our acrylic grounds.

Printed Images

Chelsea's Print

Chelsea’s Print

Etching Zinc with Copper Sulfate Mordant Test 8 >