Photoperiod - what is the appropriate 'winter'?

[Leafmite]

I quite enjoy the fluorescents...our dim winter days now seem as bright as summer and it takes the chill out of the room.

[voyager]

As an after thought, I'd like to add the following:

I have grown a number of plants at one time or another where consideration for their reaction to photoperiodicity was required to carry them through their life cycle.

While not having explored this more than just mentally noting what seems to have been their reaction to changes in the photoperiod, my feeling is that, at least for most orchids, worrying about the photoperiod is a non sequitur.

Too much or too little light intensity is a primary concern.
Length of day is of little, if any, concern for orchid cultivation, at least for most orchids.

While orchids are found from the tropics to the Arctic, maybe even the Antarctic, day length seems to be of little concern to them.
With little doubt, they originated in the tropics under fairly consistent evenly split day/night periods.
All recommendations for orchid day length I've ever seen have suggested 12 hour days +/- an hour or so.

JMO and I am open to more knowledgeable opinions.