Try counterstaining the immuno slides with giemsa rather than performing the
bleaching technique.  I use the May Grunwald giemsa following DAB.  The melanin
pigment will stain green and contrasts nicely beside the brown DAB.

Dr. H Kamino originally published counterstaining with azure B to color melanin.
I learned this trick from her when she was the chief of dermatopathology here at
Duke.

We routinely use this combination.  One note of interest, sometimes the DAB
color reaction is enhanced or altered because of prior treatment of the tissue,
such as antigen retrieval or enzyme digestion.

Jim Burchette
Duke Immunopathology