We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
110 CINEMATOGRAPHIC ANNUAL
the daguerreotype plate, which instrument was termed a "photograph meter." By the aid of this meter one was able to determine the exposure necessary to produce a visible impression on the sensitive material. This method was extremely crude and was not very reliable but it no doubt laid the foundations for the work which was carried on some years later by two men in England, Hurter and Driffield, who were amateur photographers, but whose prime interest in photography was the production of images which were true to nature. In January 1891 Ferdinand Hurter states in the opening sentence of his paper "The Action of Light on the Sensitive Film" that "the function of photography is the production of permanent images of material objects as true to nature as possible." Hurter's use of the words "sensitive film" must not be taken literally as he used the word film to represent that layer of sensitive material which was coated on a glass plate.
Ferdinand Hurter was a Swiss who began the study of chemistry at an early age, which later led him to be apprenticed to a dyer, in which practical field of chemistry he achieved notable success. He went to England some years later where he eventually became chief chemist and technical adviser of the United Alkali Company.
Vero C. Driffield, an Englishman, though intending to become an engineer, became interested in the practice of photography. His engineering studies, however, led him eventually to join the same firm with which Hurter was connected and the two men became great friends. Hurter acquired his interest in photography due to Driffield's continual experiments in this general field and for several years these two men worked together in an attempt to study the underlying principles of the action of light on a light sensitive material. It must be remembered that at this time the collodion plate was practically the only sensitive material at the disposal of the photographer. It was known generally that the photographer had to expose his plate to suit the light and great difficulty was experienced in the early stages of photography in the estimation of the correct exposure. Naturally there was much guess work connected with photography of that day. Hurter and Driffield's first problem as they saw it was to devise some means of accurately measuring the actinic power of daylight. This work led to the discovery of their actinometer. data on which is incorporated in a specification drawn up by Hurter on the 23rd of April, 1881. For several years the attention of these two men was absorbed by the general subject of actinometers.
In May 1890 the first joint work of Hurter and Driffield was published under the title "Photochemical Investigations and a New Method of Determination of the Sensitiveness of Photographic Plates." This paper led to a discussion of negative density, opacity, and transparency; means of measuring densities; study of development; gradation, which was referred to by these men as the "ratio of the densities;" intensification and reduction; ending finally with speed determination of sensitive plates.
It was Hurter and Driffield who devised the means of graphically showing the action of light on a photographic emulsion by plotting