In this test we prepared six plates with a 400 grit sandpaper aquatint using BIG ground. We etched the plates for 1 minute, 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 30 minutes increments.
Date: December 8, 2011
Researcher’s Name: Laura Sheys and Andrea Santos
Plate Material: .032 Copper
Plate Size: 3″ x 3″
Room Temperature: 75
This test was done with six plates all prepared in the same way. The copper plates were polished with Putz Pomade, steel wool, and a scraper to remove large marks. 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 ground was applied using a hand roller and hardened in the oven at 220 degrees for 7 minutes. On the plates we laid 400 grit sandpaper face down and ran it through the etching press a total of 8 times. After each pass we slightly turned the sandpaper in a clockwise motion to ensure an even impression. We rinsed the plate well under running water. There was about 50% bare copper visible under magnification.
The plate was rinsed well under-water after prepping the aquatint at the press. The plate was etched in a vertical etching tank of 38° Baume Ferric Chloride.
Timed Application of Mordant
Each plate was etched for different amounts of time: 1 minute, 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 30 minutes. We noticed that the plates etched for longer than 10 minutes had dark streaky oxidation on the surface. The ground held up well except for the 30-minute plate, which rubbed off of easily after etching.
Removal of Grounds
The ground was removed with a clean rag and Soy Solv. After we removed BIG the plates were rinsed in water and deoxidized in the plate brightener bath made of distilled white vinegar and salt (1 gallon/1 cup). It took a few applications and a toothbrush to scrub the ground completely off.
After Bath Evaluation
The plates were all slightly different. The 1-minute plate had a lot of flat area with distinguishable shallow dots. The mid-range plates have a moon crater surface. The 20-minute plate is mostly bubbly etched areas with some unetched areas of copper remaining. The 30-minute plate was entirely bubbly with no flat copper visible.
The plate was inked using Daniel Smith Creamy French Black thinned with a drop of #00 burnt plate oil. The ink was carded on with mat board scraps, wiped in gentle circular motions with used tarlatan, and then palm wiped.
Paper Type: Hahnemuhle Copperplate
Paper Soaking Time: 15 minutes
Press Blanket Setup: 2 blankets, 6.5 pressure, small tabletop Takach
The proofs were even-toned and darker than expected. The 20-minute and 30-minute proofs were both black, although the 30-minute proof is definitely darker. The 10 and 15-minute proofs were dark grey, the 5-minute proof is dark grey, and the 1-minute proof is medium grey. It looks like etch times depended on the amount of ground removed by the sandpaper.