The quantitation of fluorescence by photography.

A method based on theory has been developed for the photographic quantitation of fluorescent substances. DNA stained with ethidium in agarose gels is used as an example of an application of this method. In the course of developing this method we have demonstrated that the empirical methods employed by others authors can give rise to large systematic errors. We have also developed an approximate method based on photographic theory, avoiding the use of digital integration which is required by the rigorous method.