Fan/Ventilation (How to Light Proof?)

Was wondering how some deal with light proofing their fans. Do you use vent covers? Black Screening? I want to make sure no light is getting in at all.

Any suggestion would be appreciated..

Try Using Some Ducting And Put Some Uturn In The Routeing Light Cant Go Around Corners And Vent Covers Help.

Does anyone know how to setup a ventilation setup on panda film??? I built my own tent and im trying to get different ideas on how to setup ventilation but have no clue any help would be appreciated