Both Olya and I concluded that the the best application of airbrushed Z-Acryl was 23 rounds (See basic ground applications). I will determine if 20 rounds will be sufficient to create a smooth tone. Again we are using 42° Baume Ferric Chloride mixed with Gum Arabic taken directly from a vertical etching tank on plate one and the studio mix spitbite on plate two. Each spitbite application is brushed onto the plate with a sumi e bamboo ink brush.
Date: June 22, 2010
Researcher’s Name: Sarah Zidonik
Plate Material: .032 Copper
Plate Size: 4 in x 6 in
Room Temperature: 78°
Each 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. A basic airbrush sprayed aquatint was applied to each test plate in 20 rounds (see Basic Ground Applications). In each case the airbrush was opened only a small amount to allow for the finest spray possible, and each plate was sprayed from a distance of 16-18 inches away.
Plate one was etched with a mixture of gum arabic and 42° Baume Ferric taken from the etching tank. Plate two was etched with the shop mix spit bite.
Timed Application of Mordant
Below is a diagram of application times.
Removal of Grounds
The grounds were effectively removed using a stripper bath of Arm & Hammer Washing Soda and water (100 grams/1 liter). The plates were rinsed in water and deoxidized in the brightener bath made of distilled white vinegar and salt (1 gallon/1 cup). Immediately following the brightener bath they were dried with a clean rag and blow dryer.
After Bath Evaluation
The aquatint has stayed on the plate through etching.
The ink used was a mixture of 50% Graphic Chemical Bone Black and 50% Charbonnel RSR, plus ½ teaspoon of #3 plate oil (to about 2 tablespoons ink). The ink was carded onto the copper plate with mat board scraps, wiped with used tarlatan, and then palm wiped.
Paper Type: Hahnemule Copperplate
Paper Soaking Time: 3 Hours
Press Blanket Setup: Sizing catcher and pusher, 11.5 pressure, Small Takach Press
Both degrees of Ferric etched the plates, and there are no negligible differences between the outcomes of each test. I conclude that either source of Ferric Chloride in the studio can work equally as well. There are no problems of losing ground or open biting.