We use DAB as chromogen in ICC-studies. At the moment I am wondering why
we get do different shades of coulours from almost black, pale very nasty
looking dark brown to bright orange-brown.
I do not like it, I would like to have the same nice brilliant colour
every day. Are there any ideas about may be the chemical process behind
this. Is it a matter of concentration (which is the same always) or
temperature or what.
Any comments and help to get a reproducible nice brilliant colour are
highly appreciated.

Dr. Heike Grabsch, Germany