Examine dpi of Pictures in Books with Emoscopgreenspun.com : LUSENET : Minox Photography : One Thread
Emoscop is convenient for examine the lines per mm of printed pictures in various books.
I use an EMO-Optik Seibert Emoskop in microscope mode at 25 x to examine the B&W pictures in several books:
- Newspaper (Toronto Star) 3 line pair/mm = 150 dpi
- Joseph D. Cooper: The MINOX MANUAL : 4 lp/mm = 200 dpi
- Hubert Heckmann: MINOX Variations in 8x11 : 5 lp/mm = 250 dpi
- Alfred Stiegliz in APERTURE MASTERS OF PHOTOGRAPHY : 5 lp/mm = 250 dpi
- Andy Warhol Photography: 6 lp/mm = 300 dpi
- Lens Work magazine : 7 lp/mm = 350 dpi
- Some Canada Post stamps: 8 lp/mm = 400 dpi
- Edward Weston Forms of Passion : 12 lp/mm = 600 dpi
In the printed pictures, one lp = one black dot and one white dot = 2 dots.
The basic assceptable resolution is 4 lp/mm.
5 lp/mm produces good quality pictures..
This is a good guide for enlarging negatives based on resolution of lens, ie, 4 lpmm is acceptable, 5 lpmm is good.
Note: In all the printed pictures I have examined, the grid is not arranged in horizintal/vertical manner( ++) but at 45 degrees ( X ) manner.
-- martin tai (email@example.com), April 20, 2000