Water is used as a differentiator for eosin. It is common to follow the eosin step with 95% ethanol. The ethanol aids with rinsing the slide, while the water pulls excess eosin from the tissue. This step can help with coloration control by extending the time for lighter stains and shortening the time to maintain brighter coloration. However, excess water in xylene can continue the differentiation process and can be seen after coverslipping as a pink haze on the slide.