Description

Photographic replica grating mounted on plate glass and suitable for visual.

Grating size, 25x25mm, on glass plate 50x38mm.

The gratings are:

TYPE               SIZE

1.                        300lines/mm
2.                        600lines/mm
3.                        600lines/mm
4.                        2400lines/inch
5.                        7500lines/inch
6.                        15000lines/inch