Dye tracing

Fluorescent dyes are often used in situations where there is insufficient lighting (e.g., sewers or cave waters), and where precise quantitative data are required (measured by a fluorometer).

Its disodium salt (under the trademark "uranine") was developed several years later and still remains among the best tracer dyes.

Charcoal packets may be placed along the expected route of the flow, later the collected dye may be chemically extracted and its amount subjectively evaluated.

Filter fluorometers were the first devices that could detect dye concentrations beyond human eye sensitivity.

For example, fluorescent angiography, a technique of analysis of circulation in retina is used for diagnosing various eye diseases.