CHS 25 is the finest grain film from the historical ADOX CHS film range.
Because of the cut of in spectral sensitivity at about 620nm red image tones tend to be converted to a darker grey than compared with modern superpanchromatically sensitized films.
This leads to a better separation of lips from whte skin in portrait photography and makes the use of a green filter obsolete.
The speed gap between blue and green/red gives you interesting skies with better separated clouds (comparable to a soft yellow filtering of modern films).

If developed in ADONAL/RODINAL or Neofin Blue. CHS 25 becomes ultra sharp and brilliant.
Grain is usually not a problem with CHS 25 because of its fine grain low speed emulsion so this group of developers can often be prefered over equalizing developers such as ATOMAl 49 / D76 etc.
Low speed films need to be exposed to the highlights and developed to the shadows (which is the opposite as for high speed films).
 
Processing:

1) Can be developed in almost any B/W developer
2) Stop with water only (do not use strong stop bath)
3) Fix in any fixer.
4) Water for 30 Minutes under running water with 20 deg C.
The standard processing temperature of 20 deg C should never be exceeded with these classic films. After 22 deg C the emulsion becomes very sensitive to scratching and above 25 deg C it can come off the film.