I am just testing this film (Fomapan Creative 200) with the famous W665 (Windisch) developer.
This Ortho Phenylenediamine based, ultra fine grain developer, was designed in 1941 (by Hans Windisch) and used for maximum resolution and sharpness in the 35mm film results by the Luftwaffe during the bombing in WWII.
A kind of solarisation is formed which is removed after the fix process by a 2-3% Acetic Acid or Hydrochloric Acid and then a very fine grained negative is the result. After the war the receipture has been sold for decades under Perutz W665 which company was also bought by Agfa-Gevaert (merged in 1964) till the end of the 60's.
The problem is that there is no source for the modern type film emulsions and W665. So everything must be tested up from zero.
My first 35mm results with Rollei Pan 25 are finished. E.I. 25 and from 40x50cm no grain to focus with my Peak focusser. With the mentioned Fomapan Creative 200 (E.I. 100) just some small grain to focus on.
Why Agfa (Perutz) stopped making this W665 is not clear to me.
Maybe the removal of the solarisation layer was too complicated in a general process for accepted film development. How more I have done with this 1941 developer, how more impressed I am with the resuls.
Best regards,
Robert
(Always underway with his (Leica) M7

)