Photo Etchineers

Datasights - Glossary of Terms

Throughout our website we may use some terms which you are not familiar with, so therefore we have included this page where some terms will be explained in plain English.

Graticule Glass or other substrate with an image formed of fine lines, dots, numerals etc. placed in the focal plane of an optical instrument.
Gobo Glass or other substrate imaged with text or pictures which is placed in a lamp to enable the projection of the image on to a suitable surface.
Evaporation Coating The process of applying a microscopically thin film of material, usually metal on to the surface of a substrate by heating the metal in a vacuum.
Thin Film The film applied by evaporation coating.
Micron A common measurement used in the manufacture of graticules for specifying line widths, positions etc.
There are one thousand microns in one millimeter.
Therefore 1 micron = 0.001mm
Dichroic Multi layered evaporated coating applied to glass substrate to produce accurate and rich colours.
These coatings have the unusual property of appearing to change colour depending on the angle viewed from and transmitting and reflecting opposite colours.