Archived posting to the Leica Users Group, 1999/06/05

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Subject: [Leica] image quality of old prints
From: Erwin Puts <>
Date: Sat, 5 Jun 1999 10:24:42 +0200

Glen wrote in part:

> I am terribly humbled by these antique pictures; I cannot produce this type
> quality with my high tech gear.  The sharpness, gradation, and other visual
> characteristics of these prints are breathtaking.  I realize that these
> are contact prints, but are the wonderful films and lenses that we use
>today in
> reality lower in quality in the essential operating parameters than those of
> that time?

The explanation of this excellent image quality is not the quality of the
lenses. But the explanation offered as modern lenses would be too sharp or
contrasty is also not true.
The true story is this: whatever the optical quality of a lens, as soon as
you start enlarging the negative, image degradation (by flare in the
enlarger, optical defects in taking lens and enlarger lens etc)  will
occur. Handheld shooting and vibration through motion will also occur. All
the antique pictures were made on tripod!.
But by far the most important cause is the large negative area, which
translates into any object detail being recorded by a large area of silver
grains,producing the exceptial smoothness of gradation of antique prints.
Add to this yet another factor: the resolving power of the eye and you have
the explanation. The eye at normal viewing distances can at most resolve 5
line/pairs per millimeter. (Of course in limiting cases it will go as high
as 10 lp/mm, but that is not the 'normal' case). If a lens is used in a
camera that will be used for contact prints, the resolving power of that
lens needs to be 5 lp/mm too. So at this small value the edge contrast will
be acceptable too. Now to design a lens with 5lp/mm over most of the image
area at a very modest aperture is not too difficult and can be done with a
fair amount of aberration content left in the lens (you will not enlarge so
you will not see it).
To recap: large silver amount per image detail for smoothness, tiny
resolving power for contact printing and limiting resolution of the eye are
the secret behind this antique image quality.
The   humbling experience is mine too.
Once I did a comparison with a group of photography students to study the
image degradation when going from 35mm (Leica) to hasselblad and to 8x10
inches. (The same film in all instances). The contact print (with a modern
Sinar camera and modern super sharp Rodenstock lenses) was stunning in its
richness of image quality. It is here where digital prints will be at the
loosing end for a long time to come.

I managed to convey the same "8x10-inch-contact-print" when using the Leica
on tripod and Techpan film withh a CC40C filter and enlarged to 8x10 inch
with a good quality enlarger.