February 19, 2015 (printed 2/24)
Researchers: Audrey Blood / Jenny Gover
Room Temperature: 67 degrees F
Materials: Pledge Floor Care Finish, Golden GAC-100, Golden airbrush medium, Golden flow release, Speedball India Ink
Abstract: Refining our stop out mixture
Edinburgh Mix #7 (plate 20)
10 tsp Pledge Floor Care Finish
1.5 tsp Golden GAC-100
3 drops Golden Flow Release
3 drops Golden Airbrush Medium
4 tsp Speedball India Ink
Stop Out Mix #1
1/2 tsp Golden GAC-100
1/2 tsp Pledge Floor Finish
5 drops Speedball India Ink
Stop Out Mix #2
1 tsp Golden GAC-100
1/2 tsp Pledge Floor Finish
10 drops Speedball India Ink
Edinburgh Mixture #7 was stirred gently and then sprayed through the Badger airbrush on the finest setting onto a 4.5″ x 6″ copper plate at a distance of 6 to 8 inches with approximately 20 passes with the spray barely visible coming out of the airbrush. It was set in the drying box for 20 minutes.
We then made two stop out mixtures. Stop out mixture #1 was 1 part GAC-100 to 1 part Pledge Floor Finish with 5 drops of India Ink as a colorant. Stop out mixture #2 was 2 parts GAC-100 to 1 part Pledge Floor Finish with 10 drops of India Ink as a colorant. We then painted the mixtures onto opposite sides of the aquatinted plate using a variety consistencies as well as different brush sizes and marks.
The plate was etched on 2/24 in 37 degree baume ferric chloride for 20 minutes. It was placed in the stripper bath of 3 cups washing soda to 12 liters of warm water for 10 minutes, rinsed, dried, and printed.
The Edinburgh Mixture #7 is our final aquatint mixture. It produced a fine, even, dark tone and held up well over several weeks on the shelf. This project is finished!
Stop out mixtures #1 and #2 had similar flow and viscosity. Mix #1 was slightly lighter and thinner, and sat flatter when dry than mix #2. Mix #2 was thicker and darker. It dried in the same amount of time and seemed more comparable to the consistency of the Z-Acryl stop out. Both mixtures painted on accurately and did not bleed beyond where they had been applied.
Both mixtures came off easily after etching with approximately 10 minutes in the stripper bath.
The plate was printed a Takach press using 2 sizing catchers at 4.5 pressure. Ink: Charbonnel #55981 oil-based etching ink with 2 drops 00 plate oil. Paper: Hahnemuhle copperplate white. The aquatint printed very fine and dark, with an even tone. The areas of the plate that had been covered with stop out were clean and bright with both stop out mixtures. This led us to conclude that the exact proportions of the mixture could be flexible. The consistency of a stop out mixture could be adjusted based on individual preference. We decided to stick with a 1:1 mix of Pledge and GAC-100 because GAC-100 is more expensive, and to increase the amount of ink in order to give the mixture a little more color.