How light proof must i be?

Okay so i have a piece of duct going from my veg cab to my flowering cab i have done quite a bit to eliminate the light coming threw the ducting but i still have not completely eliminated it, when i look down into the duct i can see light, however when i put a white piece of paper a few inchs in front of the duct i can see no light reflecting off of the piece of paper, what do you guys think is this light proof enough?

Is the light coming THROUGH the duct or through a hole somewhere?

Should be fine. I have run tents and had open vents without any issues.

i use two 90 degree elbows painted black inside and put together in the shape of an "S"

No brighter than a full moon. I believe I heard as a general rule.

Bakatare666 said:

Is the light coming THROUGH the duct or through a hole somewhere?

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The light is coming threw the duct.

NoBarriers said:

Should be fine. I have run tents and had open vents without any issues.

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Thanks for the info man.

smoke and coke said:

i use two 90 degree elbows painted black inside and put together in the shape of an "S"

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My design is similar but because of the way my grow room is set up that is not possible.

topfuel29 said:

No brighter than a full moon. I believe I heard as a general rule.

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Thanks for the info man i dont think this could be any where near as bright as a full moon in fact i just tried to use my camera with out flash to capture a picture of the light and out of i think 10 pictures i only got 1 that barley showed the light.

The first 2 were taken with flash the last one was complete darkness with the light barley showing threw in the photo.

that doesnt look too bad from the pics, but you need to decide if its good. where light can leak out, it can also leak in.

Well that's what I'm worried about, i don't want the light from my veg cab interrupting my flowering cab, i don't care if the light from the flowering cab leaks into the veg cab because its going to be running 24/7, i really don't know what to do, the picture did not capture the light very well but the light is pretty visible to me when i look into the duct work, the problem is my veg cab temps are already sitting just below 90F and i don't want to add any more restriction to the ventilation via another light trap...

The light source is 2 cfls i have a piece of wood mounted directly in front of the intake duct i have 2 louvered vent caps on the intake and the exhaust and i have a light trap in side the duct that is set up like this, as i said unless i look into the vent i cant see any light not even on the mylar 2 feet away directly across the room.

Why not just put a good 90 bend in the duct, or as the other guy, but an S bend in it. I doubt you need to make the S end out of black meterial. All I have is a 90 degree bend in my duct and I see no light.