press n peel test 28

Date: November 19, 2013

Room Temperature: 68 degrees Farenheit, dry

Researcher’s Name: Cathe Janke

Test Summary
The purpose of this test was to see if the file type (pdf or tiff) and image mode (RGB or CMYK) would effect the outcome of the image.

The images were prepared in Photoshop as follows:

PLATE A, RGB as PDF
1. Image > size> 5.667, 4.25, 300 dpi
2. Layer> New Adjust Layer> Invert
3. Layer> New Adjust Layer> Color Balance Highlights- Cyan= -31 Magenta= 0 Yellow= -26
4. Layer> New Adjust Layer> Channel Mixer > monochrome
5. 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
6. Filter> Filter gallery > preset aquatint screen, 720 dpi.
7. Change to PDF

Print Settings
high quality print Acrobat 5,
check photoshop editing capabilities,
check optimize for fast web preview,
check save as PDF (continued when screen said
incompatible with earlier versions of photoshop.)
8. Layer> Flatten Image
9. Print, same as original directions, except, dpi on printer at 600 dpi.
Print Parameters Used Let Photoshop determine colors. Gray Gamma 2.2. Rendering intent=Perceptual. Presets= Plain Paper, Resolution HQ 600

PLATE B, CMYK as PDF
Same as Plate A until step 7
7. Change to CMYK. Mode> CMYK
8. CMYK as PDF
save as > format > photoshop PDF> save
9. Layer> Flatten Image
10. Print profile is different, no option to change it.
Print settings at HQ 600 dpi

PLATE C, RGB AS TIFF
Same as Plate A until step 7
7. Save as> tiff
automatic settings, none image compression. Interleaved (RGBRGB). Macintosh byte order. Layer compression. RLE (faster saves) including layers will increase file size, ok checked.
8. Layer> Flatten Image
9. Print, , same as original directions, except, dpi on printer at 600 dpi.
Print Parameters Used Let Photoshop determine colors. Gray Gamma 2.2. Rendering intent=Perceptual. Presets= Plain Paper, Resolution HQ 600

PLATE D, CMYK AS TIFF
Same as Plate A until step 7
7. Change to CMYK
Mode> CMYK
8. CMYK as tiff
save as > format > photoshop tiff> save
9. Layer> Flatten Image
10. Print, same as original directions, except, dpi on printer at 600 dpi.
Print Parameters Used Let Photoshop determine colors. Gray Gamma 2.2. Rendering intent=Perceptual. Presets= Plain Paper, Resolution HQ 600

Plate Material: .032 Copper 
Plate Size: 4.5″ x 6”

Plate Preparation
: Small scratches from the iron are visible on copper, but do not show up after etched.
The plates were beveled, polished with 00 grade steel wool, and degreased with soy sauce and bon ami.
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.

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: 15 minutes

Removal of Grounds
: Plates were saturated with Soy Solv cleaner and left to soak for 5 minutes. Ground was then wiped off easily with a rag.

After Bath Evaluation: looks like a good transfer.

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, white
Paper Soaking Time: 1 hour 
Press Blanket Setup: Takach pressure at 5.5,  2 blankets, sheet of newsprint

Test Conclusion
Comparing this test to previous ones,
test8Aproofrgbpdf
Plate A RGB as pdf,  3 tones are visible in this print. And the midtones went white.
test8Bproofcmykpdf
Plate B CMYK as pdf, The midtones went black
test8Cproofrgbtiff
Plate C RGB as tiff, 3 tones are visible in this print. And the midtones went white
test8Dproofcmyktiff
Plate D CMKY as tiff, The midtones went black

Conclusion:
It would be helpful to change the image immediately into a tiff file, so no information is lost.

press n peel test 29 >