It is seen that all of the elements that form the entire cellular structure of tissue are pretty transparent in nature. Hence, when these tissue samples are seen through the microscope, it becomes difficult to identify the structure that they have. This prevents the histologists from knowing what different tissues they are dealing with. However, there is a very simple procedure used in histology to eliminate such a problem. The use of staining dyes has become a revolutionary step in histology. There are certain dyes such as haematoxylin which is blue in colour and eosin which is red in colour. These dyes are combined together to stain the tissue samples which then makes it easier for the histologists to study the samples correctly.