This test seeks to determine the range of faintest to the darkest etched lines within a 14 minute time period. The zinc plate will be stage bitten in 2 minute intervals. This test also seeks to answer how a variable density of lines and a diversity of textures translate in the copper sulfate etch.
Date: March 18, 2011
Researcher’s Name: Chelsea Mullins
Plate Material: .040 Zinc
Plate Size: 5 in x 7 in
The plate was degreased with soy sauce that was rubbed onto the copper 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 used Z-Acryl Stop Out solution for the edges and any areas I might have missed when rolling the ground. I dried BIG in the hotbox for 25 minutes or until it was smooth to the touch without any tack. I created a hardground drawing using an etching needle.
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 fit into the file slots to keep the zinc plate in place during etching.
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 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. After 12 minutes the Z-Acryl applied to the edges of the plate peeled off and the lines widened noticeably. 14 minutes is more than enough time for dark hard ground lines. Below is the etching time table for the image.
Removal of Grounds
The grounds were removed using a stripper bath of Arm & Hammer Washing Soda and water (100 grams/1 liter). This stripper bath was relatively ineffective. I used Soy Solve and Eco Strip alternatively but it was not an easy matter to remove BIG and the Z-Acryl.
After Bath Evaluation
The plate looks properly etched with no foul biting.
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
There is no need to etch the plate any longer than 14 minutes. I achieved excellent results in this time frame.