Objective: Is a lower ppi and dpi better for our process than what we’ve been using—300 ppi image + HQ 1200 dpi (printer)? It is possible that an image with less information (that is, fewer pixels per inch) will prevent sections of the image to be blocked out by dots being placed too close together.
Room temp: 70 F humdity:dry
Plate size: 4.5X6
Plate Prep: polished with 00 grade steel wool, beveled and degreased with dish soap and soy sauce.
2 Images, one at 72 ppi and one at 300 ppi, were prepared in Photoshop:
Opened and changed to TIFF file
Image>new adjustment layer> Invert
Img>new adj layer>Channel Mixer. Selected “monochrome” option
Img>new adj layer> Curves. Four points on the curve:
Input 0/Output 45 Input 64/Output 62
Input 175/Output 171 Input 225/Output 0
-Plate A (the constant): 300 ppi image with an aquatint screen overlay at 300 ppi.
-Plate B: 72 ppi image with an aquatint screen overlay at 200 ppi (the lowest allowed ppi for a filter by photoshop)
Gray Gamma 2.2
Plate A: The above settings except print resolution set at HQ1200
Plate B: The above settings except print resolution set at 600 dpi (print res 300 dpi is too low)
Time in bath: 35 min. Etching bath notes: Both plates appear to have ragged edges where the more delicate grays mark the transition from white to shadow, but overall the image is readable and true to the original.
Ground removal: Soy Solv II
Paper: Hanhemule copperplate, soaked 10 minutes
Press: Takach, 2 thin blankets
Based on the results of this test, Bannish’s work will continue forward using a lower ppi and dpi image, at least when printing on the film using the Brother-2280DW office laser printer at the studio. Other, nicer printers may yield better results at higher dpi.