The invention provides a lighting system (1) comprising a lighting device (100) configured to provide lighting device light (101) with a variable spectral distribution (SD), wherein the lighting system (1) comprises a control system configured to control the spectral distribution (SD) of the lighting device light (101), wherein the lighting device (1) comprises at least two lighting modes (M1,M2), wherein: 5 (i) in a first lighting mode (M1) the lighting device (1) is configured to provide white light (101) with a first spectral distribution (SD1) in the visible with a first spectral intensity P1, the first spectral distribution (SD1) having a spectral intensity gap (G) configured in the spectral range of 430-600 nm, the spectral intensity gap (G) having a spectral gap width (GW1) of at least 20 nm and a maximum spectral gap intensity PG1 of lighting device light (101) within the spectral intensity gap (G) of PG1/P1≤k, wherein k is a predefined intensity ratio value, and (ii) in a second lighting mode (M2) the lighting device (1) is configured to provide white light (101) with a second spectral distribution (SD2) with a second spectral intensity P2, with a relatively enhanced intensity P2* of the lighting device light (101) in the same spectral range of the spectral intensity gap (G) of the first lighting mode, wherein P2*/P2>k.