Digital BW, The Print

Martin,

thank you for comment. Here are the benchmark data of an 80 years old Zeiss
Tessar 4.5/300mm. I hope the date dont mess up during transport to this
list...

angle off-axis: 0    5   10   15   20   25  _28_  30   degrees

     f/4.5    80   60   40   15    8   30   12    0   lines/mm
     f/22     65   60   50   35   20   50   30    6   lines/mm
     f/64     25   25   25   25   25   25   20   15   lines/mm

Actually Mr. Gainer´s figure is not correct. The theoretical limit of a
perfect lens is 22lp/mm at zero degrees. BTW - lp/mm in classical
photography is always pairs of lines!
I run into this issue by preparing an article on the new Gigabitfilm which
was published recently in PhotoVision. This film provides a resolution of
900lp/mm at a contrast of 1:1000. In this context I was taught about the
more recent data cncerning the resolution of the human eye. And of course I
was stunned to learn that the old figure of 9-10lp/mm was gained by
Helmholtz and others by imposing a test setting which is far from the actual
behaviour of our eyes. Helmholtz, one of the most famous scientist 100 years
ago has said that he would hand back the human eye to it´s creator because
it is so bad. He was wrong.
More recent research has shown that using both eyes elements 10times finer
are resolved. This is even more enhanced by the tremor.

In my praxis I am interested in a sharpness which gives me the finest
possible detail and a smooth tonality. In consequence I ended with large
negatives of 8x10" and bigger which are contact printed, not enlarged.
Having made direct comparing between 8x10" contact prints and high
resolution scans of the same subjects which were inkjet printed then in size
8x10" using Piezography as well as other inks by implementing all kinds of
curves provided by the friendly members of several mailing lists I came to
the conclusions posted in my message.

Of course I can enhance sharpness by unsharp masking in Photoshop - but this
results in a somewhat coarser tonality.

Anothet test I made was aput printing resolution. I scanned an 8x10"
negative at 300, 360, 480 and 600dpi. The prints 300 and 360dpi showed less
sharpness than the 480dpi, the best result was with 600 dpi. Printer here
was the Epson 3000 equipped with the Triton system.

The Trition system works using 3 carts containing 3 different blacks. Part
of the system is a set of tables designed for different papers. The tables
are free.
The fine tuning of the print is done in grayscale mode. After that the image
has to be changed into indicated colors where the table is applied.
The results are very nice and definitely of the same quality as the best
Piezography prints. No dots, no banding, just perfect for an inkjet print.
The Triton inks are available for all Epson printers in neutral tone and
warm tone. They last 50 years under normal exhibition conditions - depending
of course on the paper. Unfortunately Triton does not offer bulk inks.

Burkhardt Kiegeland





[Non-text portions of this message have been removed]