Farmer's reducer
noun
Far·mer's reducer
ˈfärmərz-,
ˈfȧməz-
: a 20 to 25 percent solution of hypo to which a few drops of a 10 percent solution of potassium ferricyanide are added and which is used for reducing the image density and fog density of photographic negatives and prints
Word History
Etymology
after E. Howard Farmer †1944 English photographic technician who originated it