[Histonet] haematoxylin

[Hana Peter]

Hello everyone!
Does anyone know where I can get more information about
haematoxylin-haematein-oxyhaematein chemistry?

I have a problem with my Harris haematoxylin modification (sodium iodate 
as oxidant). When I use a smaller amount of sodium iodate (about 0,1g 
per 1g of haematoxylin) I have a huge problem with precipitation. I 
don't know if this is because of the unoxidized haematoxylin in staining 
solution or because of something else.

Any help or suggestions are welcomed!
Thanks in advance!
Peter