Date: January 29, 2014
Researcher’s Name: Cathe Janke
Room Temperature: 65 degrees Farenheit, dry
The purpose of this test was to follow the original directions using a watercolor drawing brought into Photoshop to determine how the PCB film responds to the tonal range of a watercolor.
1. Kept image as a jpeg. (original file form, imported from camera)
2. Image > size> 5.667, 4.25, 300 dpi
3. Layer> New Adjust Layer> Invert
4. Layer> New Adjust Layer> Color Balance Highlights- Cyan= -31 Magenta= 0 Yellow= -26
5. Layer> New Adjust Layer> Channel Mixer > monochrome
6. Layer> New Adjust Layer> Curves, 4 points (see graph)
A: O: 45 I: 0 B: 0:62 I: 64 C: 0:171 I: 175 D: 0: 225 I:255
7. Filter> Filter gallery > preset aquatint screen, 720 dpi
8. Print, same as original directions, except, dpi on printer at 300 dpi.
Print Parameters Used Let Photoshop determine colors. Gray Gamma 2.2. Rendering intent=Perceptual. Presets= Plain Paper, Resolution HQ 300
The image was printed on the PCB film with a Brother HL2280DW laser printer. The copper plate was placed on a phone book and the film was placed on its surface print-side-down. The film was carefully heated to the plate with a tacking iron for 8 minutes at 300 degrees F.
The plates were beveled, polished with 00 grade steel wool, and degreased with soy sauce and bon ami.
Testers found that backing the plate with contact paper was most pragmatic AFTER the plate had been ironed and cooled and with the film still adhered to the plate
Etching Notes The plate was etched in a 39 degrees Baume Ferric Chloride bath in a vertical tank.
Time in Bath 20 minutes
Removal of Grounds Plates were saturated with SoySolvII and left to soak for 5 minutes. Ground was then wiped off easily with a rag.
Inking Methods: Plate was inked with Graphic Chemical Etching Ink in Bone Black, applied with a piece of mat board. It was gently wiped in an outwards motion with a piece of tarlatan. Then paper wiped, then hand-wiped.
Paper Type: Hahnemuhle, warm white
Paper Soaking Time: 30 minutes
Press Blanket Setup: Takach pressure at 5.5, 2 blankets, sheet of newsprint
After following the directions in test #11 and getting a good clear result and not getting a good result in test #12, the tester seems quite sure that the curves might not work for every image in the same way and the original drawing in this test did not have enough contrast to create a clear result.