A method for controlling a development in an automatic developing machine for a photosensitive lithographic printing plate precursor, the method comprising:
- developing a plurality of sheets of exposed photosensitive lithographic printing plate precursors with a developer containing an electrolyte while replenishing a development replenisher to keep a developer activity constant,
- wherein an electric conductivity of the developer is measured every constant period;
- a development replenisher is replenished every constant time as a time lapse replenisher in an amount based on a set value of a time lapse replenishment rate;
- a development replenisher is replenished every processing of a constant area of a photosensitive lithographic printing plate precursor(s) as a processing replenisher in an amount based on a set value of a processing replenishment rate;
- a calculated value of an electric conductivity is calculated from an amount of the time lapse replenisher and an amount of the processing replenisher;
- the set value of the time lapse replenishment rate and the set value of the processing replenishment rate are increased or decreased according to a result of a comparison of the calculated value of the electric conductivity with the measured value of the electric conductivity of the developer;
- and
- a value of a difference between the calculated value of the electric conductivity and the measured value of the electric conductivity of the developer is displayed as a degree of a developer activity.