Introduction

James Robinson is a major manufacturer of photographic chemicals, for the area of film and paper developing. The Company offers a full range of Phenidone products for black & white processing, colour developers for colour processing together with antifogging agents and other additives.

Applications

Phenidone Derivatives
These products are primarily used as black & white developing agents. The main area of application is medical imaging (x-rays) but they are also used in graphic arts applications and of course traditional black and white photography. Product choice depends on cost and technical requirements. Phenidone A is most cost effective in three part developing systems while Dimezone S, which is more expensive, is used in two part and dry formulations. Phenidone B is a niche product used in developers for specialised technology.

Antifogging Agents and Additives
Antifogging agents are used in film and paper developing to prevent "fogging" or blurring which can occur during the development of film negatives and positive paper prints. They act to enhance the contrast boundary of the image, thus aiding sharpness and resolution. James Robinson Ltd offers several products for use in this application; 5-NI, 5-MBT & 5-NBI base. All are highly effective, and are distinguished principally by tonal differences produced on the film or paper print and slight variations in concentration. 5-NI produces a brownish cast while 5-MBT & 5-NBI base produce a black cast.
5-methyl-s-triazolo-(1,5)-pyrimidin-7-ol (TM2) is used as a speed control additive in both black & white and colour film manufacture.