permanent stain

A stain that lasts for a long time without fading and does not damage the specimen. A single stain may be used, such as fast green for macerated tissues, or a tissue section may be double-stained, using, for example safranin and the counterstain light or fast green. Aqueous dyes, such as safranin, should be used before the section is dehydrated, and light green on completion of dehydration. *Clearing and *mounting follow. Compare temporary staining. See also staining.