dark
if you leave your lights on for a few minutes or even an hour or two passed 12/12... just leaves the lights off to make up for that extra time from lights staying on. rather simple. but my dumbass did that twice in a row, 2 weeks into flowering, and just made up the dark period by leaving the lights off for however long they were left on for.then put back on the original light schedule afterwards.
as far as leaving the lights off for more resin production, idk. this is my 2nd indoor grow but im usin 600 hps and 600 cfl. my other grows were outdoor n nature took care of that.