Home

Viewing
JPEG & GIF Images

Introduction
Camera Work
Group f/64
Reference Materials
The Zone System
the Ansco Memo

making a
Photograph
Image Management
Sharpness
Negative Size
Field of View & Focal Length
Depth of Field & Diffraction

FILM
Response to Light
Finding Film Speed
Making a Choice
Exposing
SEI Exposure Photometer
Developing
PMK Pyro
Rodinal
History & Credits
Slitter for the Minox.
and for 120 Rollfilm
living with Roll Film

about the PRINT
Digital Negatives

Digital Imaging
what are Pixels
Binary Arithmetic
Color and Grayscale Codes

the Scanner.
Density Range
Negative or Print?
Color or B&W?

Manipulation
Adjusting Tonal Range

the Minox
Using a Minox
Loading & UnLoading
Setting Film & Shutter Speeds
Negative Enlargeability
Slitting & Loading Film
Film Developing Tank
Equipment, Supplies, Service, Processing
References & Galleries

the Gallery

Links

Other Passions

Copyright Notice

A bit of History & Credit where credit is due!

Before Technical Pan film, Kodak produced a film called High Contrast Copy Film. It had extremely fine grain, virtually invisible with a grain magnifier, and exceptional sharpness. 11x14 inch prints from 35mm negatives could rival those from 4x5 negatives made with "normal" film. The problem was excessive contrast. As quoted in a 1979 article in "Darkroom" magazine, "In 1967, Marilyn Levy, a photo research specialist for the U.S. Army, published the formula for "POTA", an elegant simple to make developer that dramatically lowered contrast without lowering the film speed." The developer I came to favor was called "Perfection", the formula for which is now, sadly, long lost.

In the late '70s, Kodak abandoned High Contrast Copy Film, replacing it and "Solar Flare Patrol Film" with a single emulsion called Technical Pan Film. This was like a red flag to photographers, and the rush began to find the best developer. The original Kodak recommendation was of course POTA. Various dilutions of most common developers were tried and reported in endless magazine articles. Two I remember were dilute Edwal FG7 and Rodinal, each mixed with sodium sulfite. I felt that the Rodinal solution provided a bit more "edge" and chose it as my standard. Kodak followed the POTA lead and soon marketed a variant called "Technidol", first in solid form, then liquid.

I owe my thanks to whomever wrote the article for "Photographic" magazine in the late '70s.

The various available developers provide variable low value (toe), and high value (shoulder) results and can be useful in special situations where one or the other is to be optimized.

The "new kid on the block" is of course PMK Pyro, and the credit here goes to Gordon Hutchings.