I've stapled tarp material to the openings/wall to wall of the closet where light would reach the veg. area. The doors open the closet but my veg. area is within the closet. I am thinking a hole and sock or venting tube about a foot long. It's the hole and/or vent material that will let light in thru the vent I am concerned. I see most vents go out of room??
Ok thats a little better for me. You stated that your veg is contained within the closet, I'm not so clear on what's going on yet but that statement gives me a place to start.
I'm assuming that the set up is that the flowering chamber is just open in the closet and the veg chamber is a box, made of tarp, in the closet... hope this is right?
I'm also assuming that you have a way to get air into the closet and exhausted from the closet as well. which means that all you need to to is create ventilation for the veg box with in the closet. This would entail creating an intake vent for the veg chamber and an exhaust vent for the veg chamber.
Now just trying to answer the questions you posed you only need to create a 90 degree bend or two in the vent that you create for the veg chamber. This will not allow the light get around and into the flowering chamber. Remember that light only travels in straight lines so creating bends in your venting drastically reduces the amount of distance that light can travel.
Things to add:
I think you will most definitely have a powered exhaust on the veg chamber. Just having a fan blowing in the chamber will just blow the stale air around and not actually remove it from the chamber. A pc fan will be fine if your lighting is nothing too intense.
if you are not pulling air through the entire grow room closet, then the only place that will be getting ventilation would be the veg box, and even with that the ventilation that it is receiving will still be stale as you are not exhausting the closet.
Let me know if you have any more questions and i hope i was clear.
GL