For this test, two plates were subjected to different adjustments. A section of image with a wide tonal range was chosen. One plate had an aquatint screen–traditionally used in photo-polymer intaglio–embedded in the image. The other contained a diffusion dither pattern, which is a pre-existing Photoshop texture. This trial was to provide a comparison between two textures to gain a sense of if the aquatint screen, a new idea, was viable for continued consideration. Both images had the same parameters for the other adjustments, taken from our most successful test, trial 7. Curves were adjusted so that black output value was at 55. Also, a new method of removing the grounds (ie the PCB film) was tested, as researches believed that removal with the steel wool was compromising the integrity of the image.
Date: May 24, 2013
Researcher’s Name: Liz Bannish and Stephanie Gaummond
Plate Material: .032″ Copper
Plate Size: 1.5″ x 6″
Room Temperature: 71 F, humid
Plate was backed with contact paper, beveled, polished with 00 gauge steel wool, and degreased with a ratio of 1:1 soy sauce to water.
Image was opened in Photoshop. The channel mixer was opened under Image>Adjustments>Channel Mixer. In the Channel Mixer menu the “Monochrome” box was checked to give the image an appearance of black and white, even though it was technically still being profiled as RGB.
A new adjustment layer was added and under Image>Adjustments>Curves, the value for blacks was brought closer to a middle gray , an output value of 55.
The image was inverted to a negative under Image>Adjustments>Invert.
For one plate, dubbed “A,” the image had an aquatint screen embedded in it as a texture. The aquatint screen (purchased from McClain’s and usually used along with a UV exposure unit) was scanned at 720 ppi and saved as a PSD file. In Photoshop, the Filter Gallery was opened and the screen was applied to the image under Filter Gallery>Texturizer>Load filter. The section of screen that was scanned was exactly the size of the image it was applied to, about 1.4″x 5″.The values for scale and relief in the texturizer window, as applied to the screen, were set at Relief: 23 and Scaling:104. These values were somewhat arbitrary and subsequent tests in the future will see how these values affect the outcome of the image.
The second plate, dubbed “DD,” had the same above parameters save the aquatint screen. It instead had a diffusion dither pattern applied. We chose this pattern because it appeared to have the most random-seeming pattern that would feasibly not disintegrate into the halftone pattern that has been problematic in our prints in the past.
Both images were resized to 300 ppi.
Both images were printed on the same sheet of film, with the same Printer parameters: Photoshop chooses colors, rendering intent: perceptual, and Press-n-Peel print settings (plain paper, 600 dpi resolution).
Both plates were etched in a 40 degrees Baume Ferric Chloride bath.
Timed Application of Mordant
30 minutes in a vertical tank
Removal of Grounds
Grounds were removed with 00 gauge steel wool for this experiment. However, while these plates were being printed, a third plate had film ironed to it and was tested with a cleaner called Soy-Solv. The Soy-Solv successfully removed the film with no visible damages to the image. Subsequent plates will have the grounds removed with this substance to avoid any image damage relevant to the use of the steel wool.
After Bath Evaluation
No open biting, with smooth transitions between tones. Ground held up well in ferric. The aquatint embedded image looks good to print. However, the diffusion dither plate appears coarse. Both plates were printed.
Plate was inked with Graphic Chemical Etching Ink in Bone Black, applied with a piece of mat board. It was gently hand-wiped in an outwards motion with a piece of tarletan.
Paper Type: Hahnemuhle Copperplate
Paper Soaking Time: 10 minutes
Press Blanket Setup: Takach pressure at 5.5, 2 blankets, sheet of newsprint
The aquatint layer as a screen was a success and will be a valuable jumping off point for future testing. The image was smooth and retained more information from the original photograph. The tones are smooth and live within a fairly wide range. The white values need to be pushed in future tests as the range pretty much ends with them. Steel wool will no longer be used to remove the film after etching. Instead, Soy-Solv will be used in its place. The diffusion dither pattern was not as successful as the aquatint screen and will not be used in future tests.