I have no experience as far as the confocal microscope is concerned,
 but I am used to intensify DAB for conventional light microscopy.
 The DAB precipitate has a structure which could be compared with
 that of melanin and, indeed, procedures based on its reducing
 properties work quite well:
 the so-called reaction of Chevremont - Fredericq based on the
 formation 'prussian blue' (ferric ferrocyanide) gives nice blue
green precipitates at DAB containing sites;
 any silver reaction suitable for detection of 'argentaffin' or
 'APUD' cells also works great: I usually use the Masson's ammoniacal
 silver solution for this. On neurons filled with DAB labelled anti
 calbindin antibody, this produces very nice Golgi-like pictures.
 Beware, curiously enough, these reactions do not work on cobalt
 enhanced DAB.
 Hope this helps...
 
 Jean Desclin
 Associate Prof of Histology
 Dpt of Histology - Fac. of Medicine
 Brussels' Free University (U.L.B.)