HOPA

Structures	Colour
Nuclei	brown
Cytoplasm	grey-blue
Connective-tissue fibres - Collagen - Reticular - Elastic	blue blue -
Myocytes	grey-blue to grey-green
Erythrocytes	yellow-orange

Dyes:

HOPA = Hemalaun, Orange G, Phosphormolybdenic acid, Aniline blue

Cell nuclei are stained with hemalaun or Weigerts iron-hematoxylin and then counterstained with a dye mixture of orange-phosphormolybden with aniline blue.