VHL Staining School of Biomedical Sciences, Dept. of Human Biology. This is the final step which provides a colour contrast between tissue components.
Stains are dyes which react with tissue substances and routine stains show the identity of tissues.
Haematoxylin stains nuclear detail blue to black and Eosin is used as a counterstain which stains the cytoplasm, Connective Tissue fibres and Red Blood Cells orange to red. Artifacts and Problems Poor technique and other problems can create false or misleading images. These are known as artifacts . Stains for electron microscopy must be able to affect the electron beam passing through the tissue. For this reason metal based stains such as lead citrate are used.