This test will use the impression of 400 grit sandpaper in BIG ground to create an aquatint. The plate will be etched in stages from 1, 3, 5, 10, 15, 20, 25 and 30 minutes to create a light to dark gradient.
Date: September 9, 2011
Researcher’s Name: Andrea Santos & Laura Sheys
Plate Material: .032 Copper
Plate Size: 4 in x 6 in
Room Temperature: 73, low humidity.
Plate was 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. BIG ground was applied using a hand roller and hardened in the oven at 220 degrees for 9 minutes. 400 grit sandpaper is laid face down on grounded plate and ran through the press for a total of 8 times. Each time the plate has passed through the press, the blankets are lifted and the sandpaper is turned slightly in a clockwise motion. By the eighth pass, the sandpaper has rotated back to starting position. After preparing the sandpaper aquatint, the ground seems more dull and muted and there is a visible grain texture on the surface. Some ground has flaked off of the plate edges.
Each plate was etched in a vertical etching tank of Ferric Chloride at 38Â° Baume.
Timed Application of Mordant
1, 3, 5, 10, 15, 20, 25 and 30 minute step etch. Each step etch is stopped out with packing tape. At 5 minutes the red is noticeably darker with some variations in plate surface becoming visible. At 10 minutes we had similar results with a gray discoloration occurring in ungrounded areas. The ground began flaking from the edges of the plate at 15 minutes with dark spots becoming more shapely and less ambiguous. At 20 and 25 minutes we had similar results with BIG continuing to become dull and dark.
Removal of Grounds
Ground is easily removed with a clean rag and 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).
After Bath Evaluation
The tape began peeling from the plate after 30 minutes. When we removed the tape completely it pulled away more BIG. The remaining ground on the plate is speckled and resembles the inconsistent surface of an eggshell. The ground of the final 30 minute etch area is a dark magenta. The etching looks consistent with the amount of time in the Ferric but we discovered a pattern of vertical stripes – possibly due to the copper consistently falling in the same vertical motion in ferric bath.
The first proof was inked with a mixture of Charbonnel Aqua Color and Charbonnel Aqua Color oil (about a quarter amount oil to ink). The second proof was inked with Daniel Smith creamy french oil based ink. The ink was carded on with mat board scraps, wiped in gentle circular motions with used tarlatan, and then palm wiped. Plate does not seem to be holding much ink in the longer etched areas.
Paper Type: Hahnemuhle Copperplate
Paper Soaking Time: 20 minutes
Press Blanket Setup: 2 blankets, 7-10 pressure, takach press
At 1, 3, 5 and 10 minutes the plate tone is smooth with a consistent gradation of light to medium gray. At 15, 20, 25 and 30 minutes, the tone is a uneven dark gray without much gradation. There is an obvious area where ground must have degraded in the last 30 minute square – the tone is much darker and very uneven. The tones of the oil based proof are noticeably darker.