Starting seeds in rockwool.. light or no light

I have soaked my seeds over night and am planting them in grodan rockwool. Should I keep them in the dark or put them under light? thanks

yes put them under light

under light

I dont put them under light until they sprout, but obviously its works either way. my logic is they need light for photosynthesis, there is no photosynthesis without chlorophyll (green)