Welcome to Black and White Film Testing and Low Cost Darkroom Measurement Techniques 2025
This website offers amateur photographers an alternative approach to
the problems of black and white photography based on film sensitometry
measurements.
Two low cost enlarger densitometers are now available, the original electronic version,
and an ultra low cost CdS cell densitometer costing about £15 including a digital multimeter.
For the first time, this is an opportunity for many keen amateur
photographers to measure film density accurately via their enlarger.
See the "Densitometers" page for more information.
Simple spreadsheets and calibrated test film is provided to calibrate the CdS densitometer.
Film gamma and accuracy of exposure can be measured with just two exposed frames.
For the really keen photographer, a second innovation is the use of curve fitting software, available for download,
and used to analyse film test results. This enables many new parameters to
be measured and displayed, in particular, continuous curves of film gradient.
The aim at all times is to expose film correctly, that is 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 made much easier by having access to an enlarger densitometer.
Two articles, Exposure Document
and Exposure 2 Document
are also available which discuss pitfalls with some light meters, how to avoid them, difficult lighting problems
and the use of Duplexing much of which was inspired by "Dunn & Wakefield" in their excellent book "Exposure Manual".
The links and download pages have a number of introductory articles about
sensitometry with some of the historical background from the 1960's.
See the major densitometer downloads below.
Silicon sensor enlarger_photometer_14_2_20190205.pdf
2 Frame 6.66 stop simplified film gamma testing pdf 05/12/25
2 Frame 6.66 stop test Chart Spreadsheet, ods version 1.0 30/11/25
2 Frame 6.66 stop test Chart Spreadsheet, xlsx version 1.0 30/11/25
CdS cell densitometer pdf document.
CdS cell Densitometer Spreadsheet (LibreOffice)
CdS cell Densitometer Spreadsheet (Excel xlsx)
