BobYIL
Well-known
Let me shed a little light on the concepts of Latitude vs Tonality:
Imagine we are to record a bomb explosion following midnight hours and we wish to record all phases of explosion with correct tones of illumination. To accomplish it we need a multi-layered film with each layer having different sensitivities and a sensitivity stepping between each layer being something like 50.000:1 or 100.000:1 in lux terms if we are using three layers.
Similarly to duplicate the illumination tones of a sun-lit scenery we need at least 16 tones, apart from each other in 1Ev steps. Accept this 16 steps (stops) as being the dynamic range of the film; i.e. the maximum number of stops to be recorded by film, as was called the tonality. Shortly it's the range of different intensities to be captured on film simultaneously.
Latitude rather refers to the tolerance of that specific film to underexposure and overexposure but still to deliver acceptable results (i.e. photos with shorter but still usable dynamic range=tonality).
So far neither wide dynamic range nor widely tolerable exposure latitude has been accomplished with tabular grained (T-grain) films. Color-filtered (layered) films like the C-41 process B&W films (e.g. XP2) deliver wide DR and wide latitude, but also some hi-speed cubic grained films. My own experience: C-41 films are more forgiving for exposure errors (wider latitude) however hi-speed cubic grained films exhibits longer tonality (DR).
Imagine we are to record a bomb explosion following midnight hours and we wish to record all phases of explosion with correct tones of illumination. To accomplish it we need a multi-layered film with each layer having different sensitivities and a sensitivity stepping between each layer being something like 50.000:1 or 100.000:1 in lux terms if we are using three layers.
Similarly to duplicate the illumination tones of a sun-lit scenery we need at least 16 tones, apart from each other in 1Ev steps. Accept this 16 steps (stops) as being the dynamic range of the film; i.e. the maximum number of stops to be recorded by film, as was called the tonality. Shortly it's the range of different intensities to be captured on film simultaneously.
Latitude rather refers to the tolerance of that specific film to underexposure and overexposure but still to deliver acceptable results (i.e. photos with shorter but still usable dynamic range=tonality).
So far neither wide dynamic range nor widely tolerable exposure latitude has been accomplished with tabular grained (T-grain) films. Color-filtered (layered) films like the C-41 process B&W films (e.g. XP2) deliver wide DR and wide latitude, but also some hi-speed cubic grained films. My own experience: C-41 films are more forgiving for exposure errors (wider latitude) however hi-speed cubic grained films exhibits longer tonality (DR).
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I thought you were going to shed some light on it? Bombs? Explosions?
Latitude is what people who don't understand sensitometry talk about.
Latitude is what people who don't understand sensitometry talk about.