In this experiment we tested six different grades of sandpaper to create an impression into the BIG ground. Ideally we wanted the sandpaper to remove just enough ground so that it creates a smooth even tone across the plates surface after being etched.
Date: November 18, 2011
Researcher’s Name: Laura Sheys and Andrea Santos
Plate Material: .032 copper
Plate Size: 3″ x 3″
Room Temperature: 70
The copper plates were polished with Putz Pomade, steel wool, and a scraper to remove large marks. The plates were degreased with soy sauce that was rubbed onto the copper plates 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 10 minutes. We prepared six plates in all. On each plate we laid sandpaper face down and ran it through the etching press. After each pass we slightly turned the sandpaper in a clockwise motion to ensure an even impression. The following is the list of sandpaper grades and passes through the press:
100 grit 2 times
150 grit 3 times
220 grit 5 times
320 grit 6 times
400 grit 8 times
600 grit 12 times
We replaced the 400 grit and 600 grit sandpaper with a fresh sheet halfway through the process. We rinsed the plate under running water before proceeding to etch.
The plate was rinsed well under-water after prepping the aquatint at the press. The plate was etched in a vertical etching tank of 38Â° Baume Ferric Chloride for a total of 30 minutes.
Timed Application of Mordant
Each plate was etched for 10 minutes in the Ferric Chloride. After the first 10 minutes we took the plate out of the bath, rinsed it under running water, and stopped out half the plate with packing tape. We then placed the plate back in the Ferric to etch for another 20 minutes.
Removal of Grounds
The ground was removed with a clean rag, Soy Solve, and Simple Green. 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 BIG ground held up well to the etching process. However after looking at the plates under magnification we found very little exposed copper showing through the grounded plates.
The plate was inked using Daniel Smith Creamy French Black thinned with a drop of #3 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, pressure 6.5, Takach press
The printed proofs are lighter than they should be for 30 minutes of etching. It appears that the sandpaper was not pressed hard enough into the ground to expose areas of copper for etching.