Flowering is initiated by florigen which builds up in darkness and is destroyed by light. The plant starts flowering when the nights are long enough to reach the strains particular threshold a few nights in a row. Doing that initial extended period of darkness skips the transition phase. The Emerson effect is important too but it's a different mechanic.
Honestly if you just do a search for florigen you'll find tons of literature on it.
I've never done a proper side by side comparison because I have no way to keep all other variables equal but I've done strains that I've grown for years and know inside out both ways and the ones that I start that way stretch less and start stacking pistols earlier.
I always did it cause it was in the old grow bibles i think or an article from high times when i was young
DJ Short also suggests doing something similar.
What? Every plant I have flowered showed lighter at the tops only for the 1st week or so until I started seeing pistils. It’s that lightening at the tops that tip off cops in helicopters to outdoor grows.
Well, I never tried it before, and this was the only time I’ve seen pistils 4 days from flip. The other 2 times took 5-7 days to see any.
I thought it was because their night vision bounced the light from the crystals?
I got my wires crossed. You may or may not believe it but I had first wrote phytochrome and edited it to say florigen. It turns out we're both right on key points though. There are two forms of phytochrome and darkness and exposure to light convert them back and forth triggering flowering when the nights are long enough. Not quite actually destroying it but it's near enough that it's almost a matter of semantics. I found an article that explains it really well but I just got a new phone and can't figure out how to post the link.
When you leave the lights off for an extended period you have new growth that was never exposed to light and has no chlorophyll in it. A day or two after the lights come on you'd never know it.
I tested this several times and got the same results. I believe the idea of flowering hormone produced in darkness holds true from everything ive seen. I dont know that it benifits final yield, just may get you to the end faster. Theres lots of small tweaks you can do to speed things up that dont help your final yield tho, such as reduced light hours, smaller containers, pots vs in ground when outside bla bla bla