Rollei Ortho 25 plus is a successor to the earlier Rollei Ortho 25 film.
This film is a repackaging of an unidentified emulsion for document, technical and scientific photography, archival reproduction and duplicating.

Ortho 25 is suitable for BW reversal process and provides a wide exposure range of -2 EV to +2 EV (depending on development). Like other low sensitivity films, it has good resolution and fine grain.

The most important feature that makes this film different is the orthochromatic sensitization.

Rollei Ortho 25 is insensitive to the red spectrum, also called ‘red blind’. Deep red and orange turns out dark, nearly unexposed, while the blue sky and foliage appear lighter, which adds texture to the landscape.

Notably, halation isn’t prominent on this film, since the red-orange light doesn’t expose the emulsion enough.

In summary, Rollei Ortho 25 can deliver a modern and distinctive look, while still reminiscent of the early non-sensitized emulsions and brings a slight retro feel. Specific color and tonal reproduction makes orthochromatic films popular in pictorial photography.

Scans

Examples of Rollei Ortho 25 film emulation in Dehancer.