Same as isoemissive point.
Note:
The term derives from the Greek words isos: equal, and lampein: to emit light or to shine. Isolampsic is thus parallel to isosbestic.
Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 358 (https://doi.org/10.1351/pac200779030293)