Gossen Labosix enlarger exposure meter.
The Gossen Labosix is an exposure meter to be used in the darkroom for
enlarging purposes. The sensor contains a CdS light sensitive device
with a small hole and is very useful for spot measurement. On the left
side you will find the on/off switch and also the scale illumination
control. With the meter comes a special test negative used for
calibrating the meter.
The test negative is a step wedge, devided into
six squares with different density and about 0.15 D step. On top of the
meter is a knob which can be turned and also a scale. This scale
functions as a film speed index.