For this experiment, we built upon our last success with the aquatint screen and tested different values for the “Curves” option in Photoshop. We etched three versions of the same image, with all of the same Photoshop applications save for these “Curves” values. The intent was to gain a sense of which direction–and how far–to push the numbers coinciding with blacks and whites to get the best range possible.
Date: May 28, 2013
Researcher’s Name: Liz Bannish and Stephanie Gaumond
Plate Material: Copper
Plate Size: 3 plates, 0.032″ thick, approx. 1.5″X 5″ each
Room Temperature: 68 Degrees Fahrenheit, sunny and dry
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 image was cropped to the area with most tonal variation, a 1″x 4.5″ strip on the left hand of the image. It was resized to 300 ppi.
The image was inverted under Image> Adjustments> Invert.
Highlights and shadows were adjusted in Color Balance under Image> Adjustments> Color Balance. The values are as follows: Highlights- Cyan>Red +46, Magenta>Green +18, Yellow>Blue +8. Midtones: Cyan>Red -94, Magenta>Green +3, Yellow>Blue +3.
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.
An aquatint screen was embedded in the image under Filter> Gallery> Texturizer> Load Filter. The settings for the screen are scaling: 104 and relief: 25.
Lastly, Curves were adjusted under Image> Adjustents> Curves. This image was copied into three images, so that differing values for the Curves adjustment could be observed:
Plate A: Output- White 240, Black 30
Plate B: Output- White 240, Black 40
Plate C: Output- White 240, Black 50
Note: these are inverted, thus “White 240” actually is the black parts of the positive image. The 240 value was chose for the white after observing the dot pattern for that and other values through a loop.
For all images the color level values are Highlights: Cyan +46, Magenta +18, Yellow +8 Midtones: Cyan -94, Magenta +3, Yellow +3
In Channel Mixer the monochrome box is checked
All are inverted
Print Settings: Photoshop determines colors, Rendering Intent- Perceptual, “Press-n-Peel Print setup
Ferric Chloride 41 degrees Baume
Timed Application of Mordant
30 minutes in bath
Removal of Grounds
Grounds were effectively removed with Soy Solv industrial cleaner, thus eliminating the chance that the scrubbing steel wool removal would distort or lighten the image in any way.
After Bath Evaluation
Again, the images etched well. No open biting, ground held up well.
Used Graphic Chemical Etching Ink in Bone Black. Tarlatan wipe.
Paper Type: Hahnemuhle Copperplate
Paper Soaking Time: 10 Minutes
Press Blanket Setup: Press: Praga Pressure: 2 Blankets: 2 sizing catchers
All three plates resulted in the clearest image with the largest tonal ranges we’ve captured so far. We are still in want of lighter whites. With the headway we’ve decided to try the full image with the adjustment to the color balancing. In an attempt to capture the whitest whites we will mirror finish the plates before degreasing in hopes of lightening the plate tone that appears.