I guess there is a point that I wanted to make clear again when I make the statement that I believe that all 3 types of sensitometers are probably going to work fine. The point is that I would never consider trying to mathematically match film data to a scene to be photographed. That is , I would not measure the 'range' of the scene and then look at sensitometric data to find out which curve will 'fit' that range. These 'process control' sensitometers are not going to be accurate in that type of setting.
My method implies that one uses 'trial and error' to find out which film curve (ie which development time) fits the scenes range. THEN when one wishes to try a new film or developer on a similar scene, the 'process control' curves of the known and unknown film can be matched. This saves re-doing the 'trial and error' again with the new film or developer. Another way of putting it is that the sensitometric data that one is able to easily obtain is going to be too far removed from the actual scene to do a 'mathematical' matching of scene range to film curve. If one wanted to do a 'mathematical' matching one WOULD need to be concerned with spectral composition of the sensitometer light source, sensitometer exposure time etc. And even then one may need a different sensitometer and different test exposures for different scenes. Furthermore, the range of the scene is not consistently related to the range of intensities behind the lens, because of flare and such. So, some type of film plane reading would be needed. Again, at this point one is 'way out there' in unneccessary complexity.
Last edited by ic-racer; 04-09-2007 at 03:07 PM. Click to view previous post history.