Selectol Soft or Ansco 120 or Beer's A are soft developers
because they use Metol only. Add hydroquinone and contrast
will build. The higher the ratio of hydroquinone to metol the
higher the contrast. Ansel Adam's version of Ansco 130 is
another example. Metol and glycine are combined for
low contrast. The hydroquinone portion is held
separate then added to the combination in
varying amounts to increase contrast.

Softer yet. I've experimented with a phenidone only
developer. If one can do without true blacks then
a phenidone only developer may do. Dan