A Processor for Spectrographic Plates

Photographic plates used as ion detectors in mass spectroscopy were originally processed manually by rocking with the appropriate solution in stoppered glass cylinders (1). This practice has been continued by many mass spectroscopists because it is simple and requires only the simplest apparatus. On the other hand use of mechanical equipment to aid in standardizing processing conditions has become the accepted practice in emission spectroscopy (2). Commercial processors are available for plates up to 14 inches in length, but none will satisfactorily accept the 2 × 15 size frequently used in mass spectrography. A custom-made processing apparatus for such plates has been described by Owens (3). As an alternative to custom-made apparatus, a suitable processor has been constructed by modification of a standard laboratory bath of suitable dimensions. The Reid Vapor Pressure Bath (Precision Scientific Company, Catalog No. 74893) is designed to meet ASTM specifications for testing petroleum products but is relatively simple to convert to a processor for spectrographic plates (4). It can readily be made movable by setting it on one of the standard caster rings used for 25-1 liquid-nitrogen containers.