a container body is formed of a polymer material and contains coloring matter effective to render the body substantially opaque to electromagnetic radiation having a wave length of about 5 to about 600 nm and translucent or semi - transparent to electromagnetic radiation having a wave length of about 600 to about 800 nm . the container permits storage and transport of photosensitive fluids , for example , body fluids for test purposes which contain bilirubin and other photo - degradable substances , but at the same time the contents of the container body are apparent from visual inspection .