A calibration device for an optical scanner for optically detecting microscopic defects on object surfaces is formed on a substrate having a characteristic pattern of a plurality of different arrays of artificially created defects. Each array is arranged by size and spacing of the artificial defects to represent an actual defect size. Each artificially created defect of a given array is of the same size. Each defect is provided with a surface which in response to an incident beam of light scatters the light. The response of the system to the scattered light forms a characteristic pattern which corresponds to actual defects.

Apparatus and test film strip for evaluation of a film processor, particularly an x-ray film processor, based on a photodetector signal sequentially indicating the optical density of graded density test areas on a developed film and comparing the output thereof to a preselected voltage relating to the acceptable/too dark threshold of an unexposed or base fog area, the acceptable or too light threshold of a maximum density or dark area and the acceptable/too light and acceptable/too dark threshold of a medium density test area. Sequence testing of the graded density areas is functionally related on a single film strip to timing marks, adapted to be read by photodetector and timing circuitry, the timing marks and graded density test areas being linearly spaced and relatively disposed along the length of film strip.

A densitometer providing simultaneous sensing of the density in precisely adjacent portions of plural adjacent tracks. The densitometer preferably operates with stellar a pattern in which two reference tracks have been photographically recorded either side of a central specimen track of a star. The simultaneous detection of the three tracks insures a high degree of alignment between the reference and star tracks so that the correlation of their relative positions is a more accurate indication of the shift between the reference and star tracks. Alignment controls and the ability to microscopically view the radiation path through the densitometer facilitates set-up of the system to the high accuracy of results that it can achieve.

A support system for an equipment housing includes a pair of screw-adjustable legs at one end of the housing and a pivoting trestle at the other end. The pivoting trestle is made of two channel members, one nested inside the other. The channel members have side walls, and a bolt extends through holes in the side walls to pivotally mount one member with respect to the other. Alternatively, the members can be pivotally connected together using a ball-and-socket or cylinder-and-sleeve connection. The housing can be levelled by adjusting the effective length of the two legs, and the trestle automatically pivots to accommodate these adjustments as they are made.

An electrophoresis apparatus for automatically performing medical assays includes an electrophoresis platform which cooperates with a gantry assembly. The electrophoresis platform and the gantry assembly are movable along paths that are perpendicular to each other. An applicator assembly includes pipettes which transfer fluid samples from a specimen tray to an electrophoresis plate mounted on the electrophoresis platform. The electrophoresis platform then moves to a position into the gantry assembly, where electrophoresis is conducted to separate the samples into different fractions. The electrophoresis platform then moves beneath a reagent pouring station where a reagent is applied to make the separated fractions fluoresce under ultraviolet light. The electrophoresis platform is then moved beneath the gantry assembly again, and an air knife in the gantry assembly spreads the reagent. After incubation and drying of the electrophoresis plate, the electrophoresis platform and gantry assembly are moved relative to one another while the electrophoresis plate is read with the aid of ultraviolet lamps and a photomultiplier tube mounted in the gantry assembly. The gain of the photomultiplier tube is automatically adjusted and the data gathered is automatically edited to remove background noise. The edited results can be printed or displayed on a video monitor. Techniques for calibrating the electrophoresis apparatus are also disclosed.