press n peel test 38

Date: February, 2014

Room temp: 71 humdity:dry

Researcher’s Name: Liz Bannish

Test Summary: Does lpi (lines per inch) as dictated by the printer affect image quality?

Plate material: Copper 0.032

Plate size: 4.5X6″

Plate Prep: polished with 00 grade steel wool, beveled and degreased with dish soap and soy sauce.

Image was 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. 3 points on the curve:
Input 20/Output 0
Input 170/Output 109
Input 255/Output 210
Printer settings:
HQ1200
Gray Gamma 2.2
Print option–shape: round

Plate A: All of the above settings except the lpi (lines per inch) was kept constant at 53 lpi

Plate B: All of the above settings except the lpi was changed to 80 lpi

Time in bath: 35 min. Etching bath notes: both plates etched fine, plate A already has visible loss of detail (probably inherent and only more easily noticeable after bath). Both plates etched well, stop out intact as before bath

Ground removal: Soy Solv II
Paper: Hanhemule copperplate, soaked 10 minutes
Press: Takach, 2 thin blankets

test18.A.plate Plate A after etch

test18Afilm

 

Plate A, film after ironing.

test18B Plate B, after etch

test18.B.film.Plate B, film after ironing

Conclusions:

test18Aproof

 

test18Bproof

LPI DOES affect image quality. In this case, an lpi higher than 53 is better, as shown by plate B with 80 lpi. More detail is held and loss of information (as shown in prints by harsh, white, diagonal lines where tonal shift is present) is lessened at high lpi. Plate B will be used in the next test, where a higher lpi image will be compared.

press n peel test 39 >