orthochromatic

UK: /ˌɔːθəʊkrəʊˈmætɪk/ US: (ôr′thə krō mat′ik, -thō krə-)

WordReference Random House Unabridged Dictionary of American English © 2026

or•tho•chro•mat•ic  (ôr′thə krō mat′ik, -thō krə-), adj. [Photog.]

1. Photography representing correctly the relations of colors as found in a subject;
   isochromatic.
2. Photography (of an emulsion) sensitive to all visible colors except red;
   isochromatic.

• ortho- + chromatic 1885–90

Collins Concise English Dictionary © HarperCollins Publishers::

orthochromatic / ˌɔːθəʊkrəʊˈmætɪk/ adjective

1. of or relating to an emulsion giving a rendering of relative light intensities of different colours that corresponds approximately to the colour sensitivity of the eye, esp one that is insensitive to red light
   Sometimes shortened to: ortho
   Compare panchromatic