Abstract
Sections stained with haematoxylin and eosin showed maximum optical density (OD) at 536 nm, with a second peak at 600 nm. Sections stained with only eosin showed a peak at 536 nm, whilst those stained with haetnatoxylin showed a peak at 600 nm. Reduction in OD at these wavelengths was used to estimate fading of the staining. Direct sunlight reduced the OD of sections mounted in 22 different mounting media by 14 to 64% at 536 nm and 12 to 51% at 600 nm.