After the war, the first thin emulsion films began to emerge, originally from Adox. Leica users, again pushing technique forward, discovered that very slow versions of these films could be used for their fine grain. However, they tended to be very contrasty, and a compensating developer was needed to tame this. At the same time it was discovered that the acutance could be stepped up to give very high definition in these films with enhanced edge effects with specially designed developers. The king of these developers was the formula introduced by Willi Beutler which reduced the amount of developing agent and increasing the alkalinity of the accelerator. This gave very high edge effects indeed and controlled overall contrast simultaneously. An added advantage was that film speed with these slow emulsions was increased - usually by about half a stop. Because the developing agent and alkali activator are stored separately, then mixed just before use, the storage life is again very long. All the film and developer manufacturers soon made thin emulsion slow films and similar high definition developers.

Over the years, film grain size in medium and fast films reduced, and the need for the ultra slow films receded. However, the intoduction of special grain films like T-Max 100 and Delta 100, gave the same fine grain as the previous ultra slow films, but they also gave some of the same problems in sudden drop-out of shadows, for instance, as the previous contrasty slow films. Many non-special grain films too evolved to have 'straight line' characteristic curves where shadow drop-out could easily occur with automatic exposure cameras in contrasty lighting conditions. The special grain films had ultra-fine grain and resolution, but their apparent sharpness sometimes did not match that of high acutance traditional thin emulsion films.

Suddenly, the Beutler formula made sense again. Just try it with T-Max 100 for instance to see what it can do for crisp definition, full utilisation of film speed and easy printability. Available direct from Fine Print with very detailed instructions in an A+B, *1.5 litre* each, pack.