On Photo-inversion

抄録

1. The photographic films of gelatine silver bromide give rise to photo-inversion by the action of SO² gas, and may have positive or negative pictures, if the concentration of SO² gas, the time duration of exposure to the gas, and the intensity of the incident light satisfy suitable conditions.
2. The concentration of SO² gas being constant, the degrees of inversion are different for different times of exposure.
3. The time of exposure being constant, the degrees of inversion are different for different concentrations of SO² gas.
4. Positive picture generally appears in a wider range of the intensity of light and of the time of exposure to SO² gas, for the weaker concentration of the gas than for the stronger.
5. There exists for photo-inversion, the commutative action between the exposures to the gas and to the light.
6. The action of SO² gas gradually weakens with time and disappears generally within several hours.
7. Photo-inversion closely resembles to solarization in the change of grains in the film.