sensitizer
/ˈsɛnsɪˌtaɪzər/Definitions
1. noun
A substance that enhances the sensitivity of a chemical reaction or process, often used in photography or other applications.
“The developer is a sensitizer that helps reveal the image in the photographic film.”
2. verb
To make something more sensitive, especially in a chemical or physical sense.
“The new chemical sensitizer was added to the formula to increase its reactivity.”