More from Crawley's article, Amateur Photographer 30 March 2002:
"....Kodak calls the effect 'acutance' and introduced a new range of films in the 1960's designed for acutance-notably a new Panatomic-X emulsion. Other makers followed or took steps to improve definition. That prompted a number of high and maximum definition developers to exploit them."
"...truly major step came in the 1980's with 'high tech grain' emulsions, such as T-Max and Delta...... About the same time it became possible to adsorb chemical molecules to the surface of grain which further enhanced performance...........However, such materials changed the developer outlook. The presence on the surface of the the halide grains of improver chemicals, as well as greater light capturing area, has made the traditional fine grain developer's solvent action on the emulsion grains undesirable. The result has been a new generation of non-solvent developers such as T-Max, Technidol, Ilfotech, Ilfosol, FX-39.......As films became finer grained, attention turned to obtaining better sharpness of the subject's main features and crispness in definition of fine detail."