b-wtechnik

Low Cost Darkroom Techniques


Welcome to Black and White Film Testing and Low Cost Darkroom Measurement Techniques


This website offers photographers an alternative approach to the problems of black and white photography based on film sensitometry measurements.

A low cost enlarger photometer / densitometer is now available for sale via Ebay, allowing, for the first time, the opportunity for many amateur and professional photographers to measure film density accurately.

A second innovation is the use of curve fitting software, available with the photometer, to analyse film test results. This enables many new parameters to be measured and displayed, in particular, continuous curves of film gradient.

If this is too daunting for some photographers, a simple spreadsheet is now available which enables manual control of test data to calculate, with reasonable accuracy, important parameters such as various film gammas and film speed.

Models of film and paper characteristics are used to help the photographer make consistent decisions regarding exposure and processing. From version 13, testing recent ideas in the real world, as opposed to controlled lighting test conditions, has quickly led to the rejection of most of the various parameters that have been investigated over the last few years.

For various reasons, the use of constant agitation it also advocated for any kind of film development.

The final proposed system of film processing is much simpler, relies on just one particular film gradient measurement, and, unlike much of the zone system, does not advocate much variation in film development time.

The proposal is also to expose film in order that the toe is utilised to its fullest extent thus making the most of available film speed and paper dynamic range. Of course this makes greater demands on our exposure techniques as the aim is to have little or no margin for exposure error.

This is another good reason for having access to an enlarger photometer. Initially, by sacrificing a single frame to a simple test shot, in each roll or cassette of film, we can easily measure how accurate our exposure estimates were.

I appreciate that most photographers are not interested in doing their own testing and so essential film data is now published in the 'Film Data' section. This is in the form of a simpler spreadsheet derived from the main graphs and data. Photographers are encouraged to suggest other film and developer combinations to be tested.

An application article, Exposure Strategy, is also available which explains how the system works in practice.

The links and download pages have a number of introductory articles about sensitometry with some of the historical background from the 1960's.

For recent updates see the downloads page.