Chemically Reactive Paper is a paper that will turn colors such as brown, blue, pink or black when bleach or solvents are used on it in an attempt to wash the ink from its surface. This Chemically Reactive Paper feature is effective primarily in document-present situations where the original document can be examined by a trained professional or scanned with a specialized 3-illumination ID scanner and analyzed with adequate forgery detection technology.
Usability in online and mobile onboarding situations is challenging as the examination is made not on the physical document but on a photograph or scanned image of it.
Ref.: https://www.gpo.gov/pdfs/customers/security_glossary.pdf