Quotes by
Ferdinand Hurter

The photographer has to expose his plate to suit the light. In doing so he cannot take account (only) of those portions of the picture which are illuminated by direct sunlight, he must have details in his shadows, and these are illuminated by the general daylight and diffused light.

We have thus arrived to the answer to the question, Can negatives be produced such as defined to be theoretically perfect ? And the answer is, They can be produced, but only by so carefully adjusting the time to the intensity of the light that the exposures may fall within that period of correct representation. No variations whatever in development will correct an under or over-exposure.

The production of a perfect picture by means of photography is an art; the production of a technically perfect negative is a science.

There is generally-accepted belief among photographers that a great amount of control can be exercised in development over the density and the general gradations of a negative, and in this respect alkaline pyrogallol enjoys a special reputation.

A rapid method of measuring the density of negatives is a desideratum not only for the scientific investigator but also for the practical photographer. In a paper published in the Journal of the Society of Chemical Industry we have shown that the speed of photographic plates can be ascertained by a very simple method, provided an instrument be at hand which rapidly, and with a sufficient degree of accuracy, measures the relative amounts of silver deposited on a plate by a series of different exposures.