Latin lcubrre, lcubrt-, to work at night by lamplight over : -, ex-, ex- + lcubrre, to work at night by lamplight
When the night lasts longer than the day, street lights become our sun...
More elucubrations: [link]
Mamiya RB67, Delta 3200
Tetenal Ultrafin plus, 1+4, 12,5min, 20C