- an oxidizing solution for lessening the density of an exposed negative.
- a developing agent.
Examples from the Web for reducer
He is not to be dreaded by widows and orphans; he is a reducer of surplusage.The Gentle Grafter|O. Henry
The destroyer of enemies,” “the reducer of the disobedient,” “the exterminator of rebels,” “he whose sword is good.Tradition|John Francis Arundell
The alkali sets the reducer in action and is called the accelerator.
Very many, if not most, slides are all the better for just a touch of a "reducer" such as follows:—The ordinary "hypo."
To prepare this reducer, take one part varnish (the same varnish to be reduced), and two parts of turpentine.Advanced Toy Making for Schools|David M. Mitchell