Enlarger with interchangeable objectives - and variable reproduction ratios, has objective matching ratio scales on different faces of a rotatable bar

摘要

The bar has a quadratic or polygonal cross section. Each face is marked with a scale matching one of the interchangeable objectives. It is fitted with a control knob to facilitate rotation. A pointer is mounted in an internally threaded block which travels along a threaded spindle parallel to the scale bar. - The pointer is pivoted and spring loaded towards the scale bar. The spindle is rotated by a handle and coupled through bevel gears to spindles which carry the mounting platforms form the objectives and the negative stage. The gearing automatically varies the relative distances between objective and negative and between negative and projection plane.